diff --git a/frontend/src/game/tts-worker.ts b/frontend/src/game/tts-worker.ts
index 18d1f20..9770c5c 100644
--- a/frontend/src/game/tts-worker.ts
+++ b/frontend/src/game/tts-worker.ts
@@ -1,7 +1,9 @@
 // Web Worker for Kokoro TTS — runs ONNX neural network inference off the main thread.
 // This prevents the 1-5 second freezes that occur when generate() runs on the UI thread.
 
-let tts: any = null
+import type { KokoroTTS } from 'kokoro-js'
+
+let tts: KokoroTTS | null = null
 
 self.addEventListener('message', async (e: MessageEvent) => {
   const msg = e.data
@@ -13,8 +15,8 @@ self.addEventListener('message', async (e: MessageEvent) => {
         tts = await KokoroTTS.from_pretrained('onnx-community/Kokoro-82M-ONNX', {
           dtype: 'q8',
           device: null,
-          progress_callback: (p: any) => {
-            if (p.progress !== undefined) {
+          progress_callback: (p) => {
+            if ('progress' in p && typeof p.progress === 'number') {
               self.postMessage({ type: 'progress', progress: p.progress })
             }
           },
diff --git a/server/src/app.ts b/server/src/app.ts
index a0b0679..5cef627 100644
--- a/server/src/app.ts
+++ b/server/src/app.ts
@@ -1,4 +1,4 @@
-import { Hono } from 'hono'
+import { Hono, type Context } from 'hono'
 import { cors } from 'hono/cors'
 import { logger } from 'hono/logger'
 import { secureHeaders } from 'hono/secure-headers'
@@ -79,7 +79,7 @@ if (process.env.NODE_ENV === 'production' && existsSync(publicDir)) {
     webmanifest: 'application/manifest+json',
   }
 
-  function serveFile(c: any, reqPath: string, cacheControl: string) {
+  function serveFile(c: Context, reqPath: string, cacheControl: string) {
     const resolved = join(publicDir, reqPath)
     // Prevent path traversal
     if (!resolved.startsWith(publicDir)) return c.notFound()
diff --git a/server/src/engine/fight-loop.ts b/server/src/engine/fight-loop.ts
index 1dafa16..1726d1b 100644
--- a/server/src/engine/fight-loop.ts
+++ b/server/src/engine/fight-loop.ts
@@ -78,8 +78,8 @@ export async function startFightLoop(options: FightLoopOptions = {}): Promise<vo
             onRoundComplete({
               round: event.data.round as number,
               hp: event.data.hp as { a: number; b: number },
-              challengeType: (event.data.result as any)?.challengeType || '',
-              winnerId: (event.data.result as any)?.winnerId || null,
+              challengeType: (event.data.result as { challengeType?: string } | undefined)?.challengeType || '',
+              winnerId: (event.data.result as { winnerId?: string | null } | undefined)?.winnerId || null,
             })
           }
         })
@@ -151,7 +151,7 @@ export async function startFightLoop(options: FightLoopOptions = {}): Promise<vo
 
 function pickMatchup(
   bots: { id: string; eloRating: number; name: string; wins: number; losses: number }[],
-  style: string,
+  style: 'elo_close' | 'random' | 'mixed',
   fightNum: number,
 ): [typeof bots[0], typeof bots[0]] {
   const sorted = [...bots].sort((a, b) => b.eloRating - a.eloRating)
diff --git a/server/src/routes/bets.ts b/server/src/routes/bets.ts
index 3bb8f81..2169924 100644
--- a/server/src/routes/bets.ts
+++ b/server/src/routes/bets.ts
@@ -103,8 +103,8 @@ betsRouter.post('/place', rateLimit(60_000, 10), async (c) => {
       odds: bet.oddsAtPlacement,
       potentialPayout: bet.potentialPayout,
     })
-  } catch (err: any) {
-    return c.json({ error: err.message }, 400)
+  } catch (err: unknown) {
+    return c.json({ error: err instanceof Error ? err.message : String(err) }, 400)
   }
 })