diff --git a/src/app/api/zxdb/releases/search/route.ts b/src/app/api/zxdb/releases/search/route.ts
index 3e31cd1..3345876 100644
--- a/src/app/api/zxdb/releases/search/route.ts
+++ b/src/app/api/zxdb/releases/search/route.ts
@@ -9,7 +9,7 @@ const querySchema = z.object({
   year: z.coerce.number().int().optional(),
   sort: z.enum(["year_desc", "year_asc", "title", "entry_id_desc"]).optional(),
   dLanguageId: z.string().trim().length(2).optional(),
-  dMachinetypeId: z.coerce.number().int().positive().optional(),
+  dMachinetypeId: z.string().optional(),
   filetypeId: z.coerce.number().int().positive().optional(),
   schemetypeId: z.string().trim().length(2).optional(),
   sourcetypeId: z.string().trim().length(1).optional(),
@@ -17,6 +17,15 @@ const querySchema = z.object({
   isDemo: z.coerce.boolean().optional(),
 });
 
+function parseIdList(value: string | undefined) {
+  if (!value) return undefined;
+  const ids = value
+    .split(",")
+    .map((id) => Number(id.trim()))
+    .filter((id) => Number.isFinite(id) && id > 0);
+  return ids.length ? ids : undefined;
+}
+
 export async function GET(req: NextRequest) {
   const { searchParams } = new URL(req.url);
   const parsed = querySchema.safeParse({
@@ -39,7 +48,8 @@ export async function GET(req: NextRequest) {
       headers: { "content-type": "application/json" },
     });
   }
-  const data = await searchReleases(parsed.data);
+  const dMachinetypeId = parseIdList(parsed.data.dMachinetypeId);
+  const data = await searchReleases({ ...parsed.data, dMachinetypeId });
   return new Response(JSON.stringify(data), {
     headers: { "content-type": "application/json" },
   });
diff --git a/src/app/api/zxdb/search/route.ts b/src/app/api/zxdb/search/route.ts
index 8d982e2..9707531 100644
--- a/src/app/api/zxdb/search/route.ts
+++ b/src/app/api/zxdb/search/route.ts
@@ -12,12 +12,21 @@ const querySchema = z.object({
     .trim()
     .length(2, "languageId must be a 2-char code")
     .optional(),
-  machinetypeId: z.coerce.number().int().positive().optional(),
+  machinetypeId: z.string().optional(),
   sort: z.enum(["title", "id_desc"]).optional(),
   scope: z.enum(["title", "title_aliases", "title_aliases_origins"]).optional(),
   facets: z.coerce.boolean().optional(),
 });
 
+function parseIdList(value: string | undefined) {
+  if (!value) return undefined;
+  const ids = value
+    .split(",")
+    .map((id) => Number(id.trim()))
+    .filter((id) => Number.isFinite(id) && id > 0);
+  return ids.length ? ids : undefined;
+}
+
 export async function GET(req: NextRequest) {
   const { searchParams } = new URL(req.url);
   const parsed = querySchema.safeParse({
@@ -37,9 +46,11 @@ export async function GET(req: NextRequest) {
       { status: 400, headers: { "content-type": "application/json" } }
     );
   }
-  const data = await searchEntries(parsed.data);
+  const machinetypeId = parseIdList(parsed.data.machinetypeId);
+  const searchParamsParsed = { ...parsed.data, machinetypeId };
+  const data = await searchEntries(searchParamsParsed);
   const body = parsed.data.facets
-    ? { ...data, facets: await getEntryFacets(parsed.data) }
+    ? { ...data, facets: await getEntryFacets(searchParamsParsed) }
     : data;
   return new Response(JSON.stringify(body), {
     headers: { "content-type": "application/json" },
diff --git a/src/app/zxdb/entries/EntriesExplorer.tsx b/src/app/zxdb/entries/EntriesExplorer.tsx
index deed8d9..8a83582 100644
--- a/src/app/zxdb/entries/EntriesExplorer.tsx
+++ b/src/app/zxdb/entries/EntriesExplorer.tsx
@@ -52,11 +52,21 @@ export default function EntriesExplorer({
     page: number;
     genreId: string | number | "";
     languageId: string | "";
-    machinetypeId: string | number | "";
+    machinetypeId: string;
     sort: "title" | "id_desc";
     scope?: SearchScope;
   };
 }) {
+  const preferredMachineIds = [27, 26, 8, 9];
+  const parseMachineIds = (value?: string) => {
+    if (!value) return preferredMachineIds.slice();
+    const ids = value
+      .split(",")
+      .map((id) => Number(id.trim()))
+      .filter((id) => Number.isFinite(id) && id > 0);
+    return ids.length ? ids : preferredMachineIds.slice();
+  };
+
   const router = useRouter();
   const pathname = usePathname();
 
@@ -72,17 +82,20 @@ export default function EntriesExplorer({
     initialUrlState?.genreId === "" ? "" : initialUrlState?.genreId ? Number(initialUrlState.genreId) : ""
   );
   const [languageId, setLanguageId] = useState<string | "">(initialUrlState?.languageId ?? "");
-  const [machinetypeId, setMachinetypeId] = useState<number | "">(
-    initialUrlState?.machinetypeId === "" ? "" : initialUrlState?.machinetypeId ? Number(initialUrlState.machinetypeId) : ""
-  );
+  const [machinetypeIds, setMachinetypeIds] = useState<number[]>(parseMachineIds(initialUrlState?.machinetypeId));
   const [sort, setSort] = useState<"title" | "id_desc">(initialUrlState?.sort ?? "id_desc");
   const [scope, setScope] = useState<SearchScope>(initialUrlState?.scope ?? "title");
   const [facets, setFacets] = useState<EntryFacets | null>(initialFacets ?? null);
-  const preferredMachineIds = [27, 26, 8, 9];
   const preferredMachineNames = useMemo(() => {
     if (!machines.length) return preferredMachineIds.map((id) => `#${id}`);
     return preferredMachineIds.map((id) => machines.find((m) => m.id === id)?.name ?? `#${id}`);
   }, [machines]);
+  const orderedMachines = useMemo(() => {
+    const seen = new Set(preferredMachineIds);
+    const preferred = preferredMachineIds.map((id) => machines.find((m) => m.id === id)).filter(Boolean) as { id: number; name: string }[];
+    const rest = machines.filter((m) => !seen.has(m.id));
+    return [...preferred, ...rest];
+  }, [machines]);
 
   const pageSize = 20;
   const totalPages = useMemo(() => (data ? Math.max(1, Math.ceil(data.total / data.pageSize)) : 1), [data]);
@@ -97,14 +110,14 @@ export default function EntriesExplorer({
       const name = languages.find((l) => l.id === languageId)?.name ?? languageId;
       chips.push(`lang: ${name}`);
     }
-    if (machinetypeId !== "") {
-      const name = machines.find((m) => m.id === Number(machinetypeId))?.name ?? `#${machinetypeId}`;
-      chips.push(`machine: ${name}`);
+    if (machinetypeIds.length > 0) {
+      const names = machinetypeIds.map((id) => machines.find((m) => m.id === id)?.name ?? `#${id}`);
+      chips.push(`machine: ${names.join(", ")}`);
     }
     if (scope === "title_aliases") chips.push("scope: titles + aliases");
     if (scope === "title_aliases_origins") chips.push("scope: titles + aliases + origins");
     return chips;
-  }, [appliedQ, genreId, languageId, machinetypeId, scope, genres, languages, machines]);
+  }, [appliedQ, genreId, languageId, machinetypeIds, scope, genres, languages, machines]);
 
   function updateUrl(nextPage = page) {
     const params = new URLSearchParams();
@@ -112,7 +125,7 @@ export default function EntriesExplorer({
     params.set("page", String(nextPage));
     if (genreId !== "") params.set("genreId", String(genreId));
     if (languageId !== "") params.set("languageId", String(languageId));
-    if (machinetypeId !== "") params.set("machinetypeId", String(machinetypeId));
+    if (machinetypeIds.length > 0) params.set("machinetypeId", machinetypeIds.join(","));
     if (sort) params.set("sort", sort);
     if (scope !== "title") params.set("scope", scope);
     const qs = params.toString();
@@ -128,7 +141,7 @@ export default function EntriesExplorer({
       params.set("pageSize", String(pageSize));
       if (genreId !== "") params.set("genreId", String(genreId));
       if (languageId !== "") params.set("languageId", String(languageId));
-      if (machinetypeId !== "") params.set("machinetypeId", String(machinetypeId));
+      if (machinetypeIds.length > 0) params.set("machinetypeId", machinetypeIds.join(","));
       if (sort) params.set("sort", sort);
       if (scope !== "title") params.set("scope", scope);
       if (withFacets) params.set("facets", "true");
@@ -165,8 +178,7 @@ export default function EntriesExplorer({
       (initialUrlState?.q ?? "") === appliedQ &&
       (initialUrlState?.genreId === "" ? "" : Number(initialUrlState?.genreId ?? "")) === (genreId === "" ? "" : Number(genreId)) &&
       (initialUrlState?.languageId ?? "") === (languageId ?? "") &&
-      (initialUrlState?.machinetypeId === "" ? "" : Number(initialUrlState?.machinetypeId ?? "")) ===
-        (machinetypeId === "" ? "" : Number(machinetypeId)) &&
+      parseMachineIds(initialUrlState?.machinetypeId).join(",") === machinetypeIds.join(",") &&
       sort === (initialUrlState?.sort ?? "id_desc") &&
       (initialUrlState?.scope ?? "title") === scope
     ) {
@@ -176,7 +188,7 @@ export default function EntriesExplorer({
     updateUrl(page);
     fetchData(appliedQ, page, true);
     // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [page, genreId, languageId, machinetypeId, sort, scope, appliedQ]);
+  }, [page, genreId, languageId, machinetypeIds, sort, scope, appliedQ]);
 
   // Load filter lists on mount only if not provided by server
   useEffect(() => {
@@ -207,7 +219,7 @@ export default function EntriesExplorer({
     setAppliedQ("");
     setGenreId("");
     setLanguageId("");
-    setMachinetypeId("");
+    setMachinetypeIds(preferredMachineIds.slice());
     setSort("id_desc");
     setScope("title");
     setPage(1);
@@ -219,11 +231,11 @@ export default function EntriesExplorer({
     params.set("page", String(Math.max(1, (data?.page ?? 1) - 1)));
     if (genreId !== "") params.set("genreId", String(genreId));
     if (languageId !== "") params.set("languageId", String(languageId));
-    if (machinetypeId !== "") params.set("machinetypeId", String(machinetypeId));
+    if (machinetypeIds.length > 0) params.set("machinetypeId", machinetypeIds.join(","));
     if (sort) params.set("sort", sort);
     if (scope !== "title") params.set("scope", scope);
     return `/zxdb/entries?${params.toString()}`;
-  }, [appliedQ, data?.page, genreId, languageId, machinetypeId, sort, scope]);
+  }, [appliedQ, data?.page, genreId, languageId, machinetypeIds, sort, scope]);
 
   const nextHref = useMemo(() => {
     const params = new URLSearchParams();
@@ -231,11 +243,11 @@ export default function EntriesExplorer({
     params.set("page", String(Math.max(1, (data?.page ?? 1) + 1)));
     if (genreId !== "") params.set("genreId", String(genreId));
     if (languageId !== "") params.set("languageId", String(languageId));
-    if (machinetypeId !== "") params.set("machinetypeId", String(machinetypeId));
+    if (machinetypeIds.length > 0) params.set("machinetypeId", machinetypeIds.join(","));
     if (sort) params.set("sort", sort);
     if (scope !== "title") params.set("scope", scope);
     return `/zxdb/entries?${params.toString()}`;
-  }, [appliedQ, data?.page, genreId, languageId, machinetypeId, sort, scope]);
+  }, [appliedQ, data?.page, genreId, languageId, machinetypeIds, sort, scope]);
 
   return (
     <div>
@@ -303,15 +315,34 @@ export default function EntriesExplorer({
                 </div>
                 <div>
                   <label className="form-label small text-secondary">Machine</label>
-                  <select className="form-select" value={machinetypeId} onChange={(e) => { setMachinetypeId(e.target.value === "" ? "" : Number(e.target.value)); setPage(1); }}>
-                    <option value="">All machines</option>
-                    {machines.map((m) => (
-                      <option key={m.id} value={m.id}>{m.name}</option>
-                    ))}
-                  </select>
-                  {machinetypeId === "" && (
-                    <div className="form-text">Preferred: {preferredMachineNames.join(", ")}</div>
-                  )}
+                  <div className="d-flex flex-wrap gap-2">
+                    {orderedMachines.map((m) => {
+                      const active = machinetypeIds.includes(m.id);
+                      return (
+                        <button
+                          key={m.id}
+                          type="button"
+                          className={`btn btn-sm ${active ? "btn-primary" : "btn-outline-secondary"}`}
+                          onClick={() => {
+                            setMachinetypeIds((current) => {
+                              const next = new Set(current);
+                              if (next.has(m.id)) {
+                                next.delete(m.id);
+                              } else {
+                                next.add(m.id);
+                              }
+                              const order = orderedMachines.map((item) => item.id);
+                              return order.filter((id) => next.has(id));
+                            });
+                            setPage(1);
+                          }}
+                        >
+                          {m.name}
+                        </button>
+                      );
+                    })}
+                  </div>
+                  <div className="form-text">Preferred: {preferredMachineNames.join(", ")}</div>
                 </div>
                 <div>
                   <label className="form-label small text-secondary">Sort</label>
diff --git a/src/app/zxdb/entries/page.tsx b/src/app/zxdb/entries/page.tsx
index c722754..effccd5 100644
--- a/src/app/zxdb/entries/page.tsx
+++ b/src/app/zxdb/entries/page.tsx
@@ -7,12 +7,24 @@ export const metadata = {
 
 export const dynamic = "force-dynamic";
 
+function parseIdList(value: string | string[] | undefined) {
+  if (!value) return undefined;
+  const raw = Array.isArray(value) ? value.join(",") : value;
+  const ids = raw
+    .split(",")
+    .map((id) => Number(id.trim()))
+    .filter((id) => Number.isFinite(id) && id > 0);
+  return ids.length ? ids : undefined;
+}
+
 export default async function Page({ searchParams }: { searchParams: Promise<{ [key: string]: string | string[] | undefined }> }) {
   const sp = await searchParams;
   const page = Math.max(1, Number(Array.isArray(sp.page) ? sp.page[0] : sp.page) || 1);
   const genreId = (Array.isArray(sp.genreId) ? sp.genreId[0] : sp.genreId) ?? "";
   const languageId = (Array.isArray(sp.languageId) ? sp.languageId[0] : sp.languageId) ?? "";
-  const machinetypeId = (Array.isArray(sp.machinetypeId) ? sp.machinetypeId[0] : sp.machinetypeId) ?? "";
+  const preferredMachineIds = [27, 26, 8, 9];
+  const machinetypeIds = parseIdList(sp.machinetypeId) ?? preferredMachineIds;
+  const machinetypeId = machinetypeIds.join(",");
   const sort = ((Array.isArray(sp.sort) ? sp.sort[0] : sp.sort) ?? "id_desc") as "title" | "id_desc";
   const q = (Array.isArray(sp.q) ? sp.q[0] : sp.q) ?? "";
   const scope = ((Array.isArray(sp.scope) ? sp.scope[0] : sp.scope) ?? "title") as
@@ -29,7 +41,7 @@ export default async function Page({ searchParams }: { searchParams: Promise<{ [
       scope,
       genreId: genreId ? Number(genreId) : undefined,
       languageId: languageId || undefined,
-      machinetypeId: machinetypeId ? Number(machinetypeId) : undefined,
+      machinetypeId: machinetypeIds,
     }),
     listGenres(),
     listLanguages(),
@@ -40,7 +52,7 @@ export default async function Page({ searchParams }: { searchParams: Promise<{ [
       scope,
       genreId: genreId ? Number(genreId) : undefined,
       languageId: languageId || undefined,
-      machinetypeId: machinetypeId ? Number(machinetypeId) : undefined,
+      machinetypeId: machinetypeIds,
     }),
   ]);
 
diff --git a/src/app/zxdb/releases/ReleasesExplorer.tsx b/src/app/zxdb/releases/ReleasesExplorer.tsx
index 0340a34..2fdf71f 100644
--- a/src/app/zxdb/releases/ReleasesExplorer.tsx
+++ b/src/app/zxdb/releases/ReleasesExplorer.tsx
@@ -51,6 +51,16 @@ export default function ReleasesExplorer({
     casetypes: { id: string; name: string }[];
   };
 }) {
+  const preferredMachineIds = [27, 26, 8, 9];
+  const parseMachineIds = (value?: string) => {
+    if (!value) return preferredMachineIds.slice();
+    const ids = value
+      .split(",")
+      .map((id) => Number(id.trim()))
+      .filter((id) => Number.isFinite(id) && id > 0);
+    return ids.length ? ids : preferredMachineIds.slice();
+  };
+
   const router = useRouter();
   const pathname = usePathname();
 
@@ -64,7 +74,7 @@ export default function ReleasesExplorer({
 
   // Download-based filters and their option lists
   const [dLanguageId, setDLanguageId] = useState<string>(initialUrlState?.dLanguageId ?? "");
-  const [dMachinetypeId, setDMachinetypeId] = useState<string>(initialUrlState?.dMachinetypeId ?? "");
+  const [dMachinetypeIds, setDMachinetypeIds] = useState<number[]>(parseMachineIds(initialUrlState?.dMachinetypeId));
   const [filetypeId, setFiletypeId] = useState<string>(initialUrlState?.filetypeId ?? "");
   const [schemetypeId, setSchemetypeId] = useState<string>(initialUrlState?.schemetypeId ?? "");
   const [sourcetypeId, setSourcetypeId] = useState<string>(initialUrlState?.sourcetypeId ?? "");
@@ -78,11 +88,16 @@ export default function ReleasesExplorer({
   const [sources, setSources] = useState<{ id: string; name: string }[]>(initialLists?.sourcetypes ?? []);
   const [cases, setCases] = useState<{ id: string; name: string }[]>(initialLists?.casetypes ?? []);
   const initialLoad = useRef(true);
-  const preferredMachineIds = [27, 26, 8, 9];
   const preferredMachineNames = useMemo(() => {
     if (!machines.length) return preferredMachineIds.map((id) => `#${id}`);
     return preferredMachineIds.map((id) => machines.find((m) => m.id === id)?.name ?? `#${id}`);
   }, [machines]);
+  const orderedMachines = useMemo(() => {
+    const seen = new Set(preferredMachineIds);
+    const preferred = preferredMachineIds.map((id) => machines.find((m) => m.id === id)).filter(Boolean) as { id: number; name: string }[];
+    const rest = machines.filter((m) => !seen.has(m.id));
+    return [...preferred, ...rest];
+  }, [machines]);
 
   const pageSize = 20;
   const totalPages = useMemo(() => (data ? Math.max(1, Math.ceil(data.total / data.pageSize)) : 1), [data]);
@@ -94,7 +109,7 @@ export default function ReleasesExplorer({
     if (year) params.set("year", year);
     if (sort) params.set("sort", sort);
     if (dLanguageId) params.set("dLanguageId", dLanguageId);
-    if (dMachinetypeId) params.set("dMachinetypeId", dMachinetypeId);
+    if (dMachinetypeIds.length > 0) params.set("dMachinetypeId", dMachinetypeIds.join(","));
     if (filetypeId) params.set("filetypeId", filetypeId);
     if (schemetypeId) params.set("schemetypeId", schemetypeId);
     if (sourcetypeId) params.set("sourcetypeId", sourcetypeId);
@@ -114,7 +129,7 @@ export default function ReleasesExplorer({
       if (year) params.set("year", String(Number(year)));
       if (sort) params.set("sort", sort);
       if (dLanguageId) params.set("dLanguageId", dLanguageId);
-      if (dMachinetypeId) params.set("dMachinetypeId", dMachinetypeId);
+      if (dMachinetypeIds.length > 0) params.set("dMachinetypeId", dMachinetypeIds.join(","));
       if (filetypeId) params.set("filetypeId", filetypeId);
       if (schemetypeId) params.set("schemetypeId", schemetypeId);
       if (sourcetypeId) params.set("sourcetypeId", sourcetypeId);
@@ -148,7 +163,7 @@ export default function ReleasesExplorer({
       (initialUrlState?.year ?? "") === (year ?? "") &&
       sort === (initialUrlState?.sort ?? "year_desc") &&
       (initialUrlState?.dLanguageId ?? "") === dLanguageId &&
-      (initialUrlState?.dMachinetypeId ?? "") === dMachinetypeId &&
+      parseMachineIds(initialUrlState?.dMachinetypeId).join(",") === dMachinetypeIds.join(",") &&
       (initialUrlState?.filetypeId ?? "") === filetypeId &&
       (initialUrlState?.schemetypeId ?? "") === schemetypeId &&
       (initialUrlState?.sourcetypeId ?? "") === sourcetypeId &&
@@ -168,7 +183,7 @@ export default function ReleasesExplorer({
     }
     updateUrl(page);
     fetchData(appliedQ, page);
-  }, [page, year, sort, dLanguageId, dMachinetypeId, filetypeId, schemetypeId, sourcetypeId, casetypeId, isDemo, appliedQ]);
+  }, [page, year, sort, dLanguageId, dMachinetypeIds, filetypeId, schemetypeId, sourcetypeId, casetypeId, isDemo, appliedQ]);
 
   function onSubmit(e: React.FormEvent) {
     e.preventDefault();
@@ -209,14 +224,14 @@ export default function ReleasesExplorer({
     if (year) params.set("year", year);
     if (sort) params.set("sort", sort);
     if (dLanguageId) params.set("dLanguageId", dLanguageId);
-    if (dMachinetypeId) params.set("dMachinetypeId", dMachinetypeId);
+    if (dMachinetypeIds.length > 0) params.set("dMachinetypeId", dMachinetypeIds.join(","));
     if (filetypeId) params.set("filetypeId", filetypeId);
     if (schemetypeId) params.set("schemetypeId", schemetypeId);
     if (sourcetypeId) params.set("sourcetypeId", sourcetypeId);
     if (casetypeId) params.set("casetypeId", casetypeId);
     if (isDemo) params.set("isDemo", "1");
     return `/zxdb/releases?${params.toString()}`;
-  }, [appliedQ, data?.page, year, sort, dLanguageId, dMachinetypeId, filetypeId, schemetypeId, sourcetypeId, casetypeId, isDemo]);
+  }, [appliedQ, data?.page, year, sort, dLanguageId, dMachinetypeIds, filetypeId, schemetypeId, sourcetypeId, casetypeId, isDemo]);
 
   const nextHref = useMemo(() => {
     const params = new URLSearchParams();
@@ -225,14 +240,14 @@ export default function ReleasesExplorer({
     if (year) params.set("year", year);
     if (sort) params.set("sort", sort);
     if (dLanguageId) params.set("dLanguageId", dLanguageId);
-    if (dMachinetypeId) params.set("dMachinetypeId", dMachinetypeId);
+    if (dMachinetypeIds.length > 0) params.set("dMachinetypeId", dMachinetypeIds.join(","));
     if (filetypeId) params.set("filetypeId", filetypeId);
     if (schemetypeId) params.set("schemetypeId", schemetypeId);
     if (sourcetypeId) params.set("sourcetypeId", sourcetypeId);
     if (casetypeId) params.set("casetypeId", casetypeId);
     if (isDemo) params.set("isDemo", "1");
     return `/zxdb/releases?${params.toString()}`;
-  }, [appliedQ, data?.page, year, sort, dLanguageId, dMachinetypeId, filetypeId, schemetypeId, sourcetypeId, casetypeId, isDemo]);
+  }, [appliedQ, data?.page, year, sort, dLanguageId, dMachinetypeIds, filetypeId, schemetypeId, sourcetypeId, casetypeId, isDemo]);
 
   return (
     <div>
@@ -291,15 +306,34 @@ export default function ReleasesExplorer({
                 </div>
                 <div>
                   <label className="form-label small text-secondary">DL Machine</label>
-                  <select className="form-select" value={dMachinetypeId} onChange={(e) => { setDMachinetypeId(e.target.value); setPage(1); }}>
-                    <option value="">All machines</option>
-                    {machines.map((m) => (
-                      <option key={m.id} value={m.id}>{m.name}</option>
-                    ))}
-                  </select>
-                  {dMachinetypeId === "" && (
-                    <div className="form-text">Preferred: {preferredMachineNames.join(", ")}</div>
-                  )}
+                  <div className="d-flex flex-wrap gap-2">
+                    {orderedMachines.map((m) => {
+                      const active = dMachinetypeIds.includes(m.id);
+                      return (
+                        <button
+                          key={m.id}
+                          type="button"
+                          className={`btn btn-sm ${active ? "btn-primary" : "btn-outline-secondary"}`}
+                          onClick={() => {
+                            setDMachinetypeIds((current) => {
+                              const next = new Set(current);
+                              if (next.has(m.id)) {
+                                next.delete(m.id);
+                              } else {
+                                next.add(m.id);
+                              }
+                              const order = orderedMachines.map((item) => item.id);
+                              return order.filter((id) => next.has(id));
+                            });
+                            setPage(1);
+                          }}
+                        >
+                          {m.name}
+                        </button>
+                      );
+                    })}
+                  </div>
+                  <div className="form-text">Preferred: {preferredMachineNames.join(", ")}</div>
                 </div>
                 <div>
                   <label className="form-label small text-secondary">File type</label>
diff --git a/src/app/zxdb/releases/page.tsx b/src/app/zxdb/releases/page.tsx
index 6aad703..aeed10a 100644
--- a/src/app/zxdb/releases/page.tsx
+++ b/src/app/zxdb/releases/page.tsx
@@ -7,6 +7,16 @@ export const metadata = {
 
 export const dynamic = "force-dynamic";
 
+function parseIdList(value: string | string[] | undefined) {
+  if (!value) return undefined;
+  const raw = Array.isArray(value) ? value.join(",") : value;
+  const ids = raw
+    .split(",")
+    .map((id) => Number(id.trim()))
+    .filter((id) => Number.isFinite(id) && id > 0);
+  return ids.length ? ids : undefined;
+}
+
 export default async function Page({ searchParams }: { searchParams: Promise<{ [key: string]: string | string[] | undefined }> }) {
   const sp = await searchParams;
   const hasParams = Object.values(sp).some((value) => value !== undefined);
@@ -16,8 +26,9 @@ export default async function Page({ searchParams }: { searchParams: Promise<{ [
   const year = yearStr ? Number(yearStr) : undefined;
   const sort = ((Array.isArray(sp.sort) ? sp.sort[0] : sp.sort) ?? "year_desc") as "year_desc" | "year_asc" | "title" | "entry_id_desc";
   const dLanguageId = (Array.isArray(sp.dLanguageId) ? sp.dLanguageId[0] : sp.dLanguageId) ?? "";
-  const dMachinetypeIdStr = (Array.isArray(sp.dMachinetypeId) ? sp.dMachinetypeId[0] : sp.dMachinetypeId) ?? "";
-  const dMachinetypeId = dMachinetypeIdStr ? Number(dMachinetypeIdStr) : undefined;
+  const preferredMachineIds = [27, 26, 8, 9];
+  const dMachinetypeIds = parseIdList(sp.dMachinetypeId) ?? preferredMachineIds;
+  const dMachinetypeIdStr = dMachinetypeIds.join(",");
   const filetypeIdStr = (Array.isArray(sp.filetypeId) ? sp.filetypeId[0] : sp.filetypeId) ?? "";
   const filetypeId = filetypeIdStr ? Number(filetypeIdStr) : undefined;
   const schemetypeId = (Array.isArray(sp.schemetypeId) ? sp.schemetypeId[0] : sp.schemetypeId) ?? "";
@@ -27,7 +38,7 @@ export default async function Page({ searchParams }: { searchParams: Promise<{ [
   const isDemo = isDemoStr ? (isDemoStr === "true" || isDemoStr === "1") : undefined;
 
   const [initial, langs, machines, filetypes, schemes, sources, cases] = await Promise.all([
-    searchReleases({ page, pageSize: 20, q, year, sort, dLanguageId: dLanguageId || undefined, dMachinetypeId, filetypeId, schemetypeId: schemetypeId || undefined, sourcetypeId: sourcetypeId || undefined, casetypeId: casetypeId || undefined, isDemo }),
+    searchReleases({ page, pageSize: 20, q, year, sort, dLanguageId: dLanguageId || undefined, dMachinetypeId: dMachinetypeIds, filetypeId, schemetypeId: schemetypeId || undefined, sourcetypeId: sourcetypeId || undefined, casetypeId: casetypeId || undefined, isDemo }),
     listLanguages(),
     listMachinetypes(),
     listFiletypes(),
diff --git a/src/server/repo/zxdb.ts b/src/server/repo/zxdb.ts
index 6345738..b9f73cc 100644
--- a/src/server/repo/zxdb.ts
+++ b/src/server/repo/zxdb.ts
@@ -63,7 +63,7 @@ export interface SearchParams {
   // Optional simple filters (ANDed together)
   genreId?: number;
   languageId?: string;
-  machinetypeId?: number;
+  machinetypeId?: number | number[];
   // Sorting
   sort?: "title" | "id_desc";
   // Search scope (defaults to titles only)
@@ -177,7 +177,10 @@ export async function searchEntries(params: SearchParams): Promise<PagedResult<S
   const offset = (page - 1) * pageSize;
   const sort = params.sort ?? (q ? "title" : "id_desc");
   const scope: EntrySearchScope = params.scope ?? "title";
-  const preferMachineOrder = typeof params.machinetypeId === "number"
+  const hasMachineFilter = Array.isArray(params.machinetypeId)
+    ? params.machinetypeId.length > 0
+    : typeof params.machinetypeId === "number";
+  const preferMachineOrder = hasMachineFilter
     ? null
     : sql`case
         when ${entries.machinetypeId} = 27 then 0
@@ -190,7 +193,7 @@ export async function searchEntries(params: SearchParams): Promise<PagedResult<S
   if (q.length === 0) {
     // Default listing: return first page by id desc (no guaranteed ordering field; using id)
     // Apply optional filters even without q
-    const whereClauses: Array<ReturnType<typeof eq>> = [];
+    const whereClauses: Array<ReturnType<typeof sql>> = [];
     if (typeof params.genreId === "number") {
       whereClauses.push(eq(entries.genretypeId, params.genreId));
     }
@@ -199,6 +202,9 @@ export async function searchEntries(params: SearchParams): Promise<PagedResult<S
     }
     if (typeof params.machinetypeId === "number") {
       whereClauses.push(eq(entries.machinetypeId, params.machinetypeId));
+    } else if (Array.isArray(params.machinetypeId) && params.machinetypeId.length > 0) {
+      const ids = params.machinetypeId.map((id) => sql`${id}`);
+      whereClauses.push(sql`${entries.machinetypeId} in (${sql.join(ids, sql`, `)})`);
     }
 
     const whereExpr = whereClauses.length ? and(...whereClauses) : undefined;
@@ -1655,7 +1661,12 @@ export async function getEntryFacets(params: SearchParams): Promise<EntryFacets>
   }
   if (params.genreId) whereParts.push(sql`e.genretype_id = ${params.genreId}`);
   if (params.languageId) whereParts.push(sql`e.language_id = ${params.languageId}`);
-  if (params.machinetypeId) whereParts.push(sql`e.machinetype_id = ${params.machinetypeId}`);
+  if (typeof params.machinetypeId === "number") {
+    whereParts.push(sql`e.machinetype_id = ${params.machinetypeId}`);
+  } else if (Array.isArray(params.machinetypeId) && params.machinetypeId.length > 0) {
+    const ids = params.machinetypeId.map((id) => sql`${id}`);
+    whereParts.push(sql`e.machinetype_id in (${sql.join(ids, sql`, `)})`);
+  }
 
   const whereSql = whereParts.length ? sql.join([sql`where `, sql.join(whereParts, sql` and `)], sql``) : sql``;
 
@@ -1733,7 +1744,7 @@ export interface ReleaseSearchParams {
   sort?: "year_desc" | "year_asc" | "title" | "entry_id_desc";
   // Optional download-based filters (matched via EXISTS on downloads)
   dLanguageId?: string; // downloads.language_id
-  dMachinetypeId?: number; // downloads.machinetype_id
+  dMachinetypeId?: number | number[]; // downloads.machinetype_id
   filetypeId?: number; // downloads.filetype_id
   schemetypeId?: string; // downloads.schemetype_id
   sourcetypeId?: string; // downloads.sourcetype_id
@@ -1754,7 +1765,10 @@ export async function searchReleases(params: ReleaseSearchParams): Promise<Paged
   const pageSize = Math.max(1, Math.min(params.pageSize ?? 20, 100));
   const page = Math.max(1, params.page ?? 1);
   const offset = (page - 1) * pageSize;
-  const preferMachineOrder = params.dMachinetypeId != null
+  const hasMachineFilter = Array.isArray(params.dMachinetypeId)
+    ? params.dMachinetypeId.length > 0
+    : params.dMachinetypeId != null;
+  const preferMachineOrder = hasMachineFilter
     ? null
     : sql`case
         when ${entries.machinetypeId} = 27 then 0
@@ -1780,7 +1794,12 @@ export async function searchReleases(params: ReleaseSearchParams): Promise<Paged
   // would produce "from `d`" which MySQL interprets as a literal table.
   const dlConds: Array<ReturnType<typeof sql>> = [];
   if (params.dLanguageId) dlConds.push(sql`d.language_id = ${params.dLanguageId}`);
-  if (params.dMachinetypeId != null) dlConds.push(sql`d.machinetype_id = ${params.dMachinetypeId}`);
+  if (typeof params.dMachinetypeId === "number") {
+    dlConds.push(sql`d.machinetype_id = ${params.dMachinetypeId}`);
+  } else if (Array.isArray(params.dMachinetypeId) && params.dMachinetypeId.length > 0) {
+    const ids = params.dMachinetypeId.map((id) => sql`${id}`);
+    dlConds.push(sql`d.machinetype_id in (${sql.join(ids, sql`, `)})`);
+  }
   if (params.filetypeId != null) dlConds.push(sql`d.filetype_id = ${params.filetypeId}`);
   if (params.schemetypeId) dlConds.push(sql`d.schemetype_id = ${params.schemetypeId}`);
   if (params.sourcetypeId) dlConds.push(sql`d.sourcetype_id = ${params.sourcetypeId}`);