6ba2976e1b5da7d1f3fd5819d35386e165f78682
diff --git a/src/games.ts b/src/games.ts
index 5417fd4894304f1651233af42dcabb8936e82757..944cf662e1fbb113843a98026d6f5809c6fde04a 100644
--- a/src/games.ts
+++ b/src/games.ts
@@ -8,6 +8,10 @@ export interface Game {
 }
 
 export async function loadGame(id: string): Promise<Game> {
+  const file = Bun.file(`./content/games/${id}/spec.ts`);
+  if (!(await file.exists())) {
+    throw new Error(`unknown game: ${id}`);
+  }
   const mod = await import(`../content/games/${id}/spec.ts`);
   return mod.spec as Game;
 }