diff --git a/server/src/engine/human-responses.ts b/server/src/engine/human-responses.ts
index 9327225..1ec93b5 100644
--- a/server/src/engine/human-responses.ts
+++ b/server/src/engine/human-responses.ts
@@ -18,7 +18,7 @@ interface PendingChallenge {
 
 const pending = new Map<string, PendingChallenge>()
 
-const HUMAN_TIMEOUT_MS = 8_000
+const DEFAULT_HUMAN_TIMEOUT_MS = 8_000
 
 export function isHumanPlayer(webhookUrl: string): boolean {
   return webhookUrl === 'http://human.local/'
@@ -231,12 +231,13 @@ export function waitForHumanResponse(
 ): Promise<{ answer: string | null; trashTalk?: string; timedOut: boolean }> {
   return new Promise((resolve) => {
     const key = `${fightId}:${botId}`
+    const timeoutMs = challenge.timeout_ms || DEFAULT_HUMAN_TIMEOUT_MS
 
     const timeoutHandle = setTimeout(() => {
       pending.delete(key)
-      console.log(`[human] ${key} timed out after ${HUMAN_TIMEOUT_MS}ms`)
+      console.log(`[human] ${key} timed out after ${timeoutMs}ms`)
       resolve({ answer: null, timedOut: true })
-    }, HUMAN_TIMEOUT_MS)
+    }, timeoutMs)
 
     const choices = generateChoices(challenge)
 
@@ -290,15 +291,16 @@ export function getPendingChallenge(
   const entry = pending.get(key)
   if (!entry) return null
 
+  const timeoutMs = entry.challenge.timeout_ms || DEFAULT_HUMAN_TIMEOUT_MS
   const elapsed = Date.now() - entry.createdAt
-  const remaining = Math.max(0, HUMAN_TIMEOUT_MS - elapsed)
+  const remaining = Math.max(0, timeoutMs - elapsed)
 
   return {
     type: entry.challenge.type,
     label: entry.challenge.label,
     prompt: entry.challenge.prompt,
     roundNumber: entry.roundNumber,
-    timeoutMs: HUMAN_TIMEOUT_MS,
+    timeoutMs,
     remainingMs: remaining,
     scoring: entry.challenge.scoring,
     choices: entry.choices,
diff --git a/server/src/engine/scoring.ts b/server/src/engine/scoring.ts
index 168e6d2..45870e6 100644
--- a/server/src/engine/scoring.ts
+++ b/server/src/engine/scoring.ts
@@ -174,13 +174,34 @@ export function scoreRound(
   }
 }
 
+const ARENA_MODIFIER_TYPES: Record<string, string[]> = {
+  speed_2x: ['speed_blitz'],
+  efficiency_buff: ['token_economy'],
+  roast_2x: ['roast_battle'],
+  accuracy_buff: ['hallucination_check'],
+  wrestling_2x: ['wrestling_match', 'roast_battle'],
+  food_2x: ['food_fight'],
+  magic_2x: ['magic_duel', 'medieval_combat'],
+  meme_2x: ['meme_war'],
+  space_2x: ['space_war'],
+  demo_2x: ['demolition', 'vehicle_mayhem'],
+  music_2x: ['music_battle'],
+  nature_2x: ['nature_clash', 'animal_kingdom'],
+  hack_2x: ['hack_battle'],
+  sports_2x: ['sports_showdown'],
+}
+
 function applyModifiers(
   damage: number,
-  _challenge: Challenge,
-  _arenaModifier: string | null,
+  challenge: Challenge,
+  arenaModifier: string | null,
   combo: number,
 ): number {
   let d = damage
+  // Arena modifier: 2x damage when challenge type matches
+  if (arenaModifier && ARENA_MODIFIER_TYPES[arenaModifier]?.includes(challenge.type)) {
+    d *= 2
+  }
   if (combo > 0) {
     d *= 1 + Math.min(combo, 5) * 0.2
   }