diff --git a/cmd/acb-worker/b2.go b/cmd/acb-worker/b2.go
index 30a95a7..138761b 100644
--- a/cmd/acb-worker/b2.go
+++ b/cmd/acb-worker/b2.go
@@ -49,15 +49,19 @@ func NewB2Client(cfg *Config) *B2Client {
 	}
 }
 
-// Upload uploads data to B2.
-func (c *B2Client) Upload(ctx context.Context, key string, data []byte, contentType string) error {
-	_, err := c.client.PutObject(ctx, &s3.PutObjectInput{
+// Upload uploads data to B2. Pass contentEncoding="" for uncompressed objects.
+func (c *B2Client) Upload(ctx context.Context, key string, data []byte, contentType string, contentEncoding string) error {
+	input := &s3.PutObjectInput{
 		Bucket:       aws.String(c.bucket),
 		Key:          aws.String(key),
 		Body:         bytes.NewReader(data),
 		ContentType:  aws.String(contentType),
 		CacheControl: aws.String("public, max-age=31536000, immutable"),
-	})
+	}
+	if contentEncoding != "" {
+		input.ContentEncoding = aws.String(contentEncoding)
+	}
+	_, err := c.client.PutObject(ctx, input)
 	return err
 }
 
diff --git a/cmd/acb-worker/main.go b/cmd/acb-worker/main.go
index d965958..240ef6f 100644
--- a/cmd/acb-worker/main.go
+++ b/cmd/acb-worker/main.go
@@ -6,6 +6,8 @@
 package main
 
 import (
+	"bytes"
+	"compress/gzip"
 	"context"
 	"encoding/json"
 	"flag"
@@ -224,14 +226,14 @@ func (w *Worker) pollAndExecute(ctx context.Context) error {
 	replayURL := ""
 	if w.b2 != nil {
 		uploadStart := time.Now()
-		replayData, _ := json.Marshal(replay)
 		replayURL, err = w.uploadReplay(ctx, claimData.Match.ID, replay)
 		if err != nil {
 			w.metrics.RecordReplayUploadError()
 			w.logger.Printf("Failed to upload replay: %v", err)
 			// Continue without replay URL - match result is more important
 		} else {
-			w.metrics.RecordReplayUpload(time.Since(uploadStart), len(replayData))
+			replaySize, _ := json.Marshal(replay)
+			w.metrics.RecordReplayUpload(time.Since(uploadStart), len(replaySize))
 			w.logger.Printf("Uploaded replay to %s", replayURL)
 		}
 	}
@@ -318,10 +320,11 @@ func (w *Worker) executeMatch(ctx context.Context, claimData *JobClaimData) (*Ma
 
 	// Convert result
 	result := &MatchResult{
-		WinnerID:   "",
-		Turns:      engineResult.Turns,
-		EndReason:  engineResult.Reason,
-		Scores:     make(map[string]int),
+		WinnerID:    "",
+		Turns:       engineResult.Turns,
+		EndReason:   engineResult.Reason,
+		Scores:      make(map[string]int),
+		CrashedBots: make(map[string]bool),
 	}
 
 	// Set winner ID from result (Winner is int, -1 for draw)
@@ -341,6 +344,13 @@ func (w *Worker) executeMatch(ctx context.Context, claimData *JobClaimData) (*Ma
 		}
 	}
 
+	// Propagate crash status from engine
+	for _, p := range claimData.Participants {
+		if p.PlayerSlot < len(engineResult.Crashed) {
+			result.CrashedBots[p.BotID] = engineResult.Crashed[p.PlayerSlot]
+		}
+	}
+
 	return result, replay, nil
 }
 
@@ -364,7 +374,7 @@ func (w *Worker) sendHeartbeats(ctx context.Context, jobID string) {
 	}
 }
 
-// uploadReplay uploads the replay to B2 and returns the URL.
+// uploadReplay uploads the gzipped replay to B2 and returns the URL.
 func (w *Worker) uploadReplay(ctx context.Context, matchID string, replay *engine.Replay) (string, error) {
 	if w.b2 == nil {
 		return "", fmt.Errorf("B2 client not configured")
@@ -376,9 +386,19 @@ func (w *Worker) uploadReplay(ctx context.Context, matchID string, replay *engin
 		return "", fmt.Errorf("failed to serialize replay: %w", err)
 	}
 
+	// Gzip compress
+	var buf bytes.Buffer
+	gw := gzip.NewWriter(&buf)
+	if _, err := gw.Write(data); err != nil {
+		return "", fmt.Errorf("failed to gzip replay: %w", err)
+	}
+	if err := gw.Close(); err != nil {
+		return "", fmt.Errorf("failed to close gzip writer: %w", err)
+	}
+
 	// Upload to B2
-	key := fmt.Sprintf("replays/%s.json", matchID)
-	if err := w.b2.Upload(ctx, key, data, "application/json"); err != nil {
+	key := fmt.Sprintf("replays/%s.json.gz", matchID)
+	if err := w.b2.Upload(ctx, key, buf.Bytes(), "application/json", "gzip"); err != nil {
 		return "", fmt.Errorf("failed to upload replay to B2: %w", err)
 	}
 
diff --git a/web/src/pages/bot-profile.ts b/web/src/pages/bot-profile.ts
index a05e11d..b492324 100644
--- a/web/src/pages/bot-profile.ts
+++ b/web/src/pages/bot-profile.ts
@@ -184,7 +184,7 @@ function renderMatchItem(match: BotProfile['recent_matches'][number]): string {
       <span class="match-result">${won ? 'W' : 'L'}</span>
       <span class="match-opponent">${opponent ? escapeHtml(opponent.name) : 'Unknown'}</span>
       <span class="match-score">${match.participants.map(p => p.score).join(' - ')}</span>
-      <a href="#/watch/replay?url=/replays/${match.id}.json" class="btn small">Watch</a>
+      <a href="#/watch/replay?url=/replays/${match.id}.json.gz" class="btn small">Watch</a>
     </div>
   `;
 }
diff --git a/web/src/pages/matches.ts b/web/src/pages/matches.ts
index 1150ac6..dc792ea 100644
--- a/web/src/pages/matches.ts
+++ b/web/src/pages/matches.ts
@@ -311,7 +311,7 @@ function renderMatchCard(match: MatchSummary): string {
           <span class="match-turns">${match.turns ?? '-'} turns</span>
           <span class="match-reason">${match.end_reason ?? '-'}</span>
         </div>
-        <a href="#/watch/replay?url=/replays/${match.id}.json" class="btn small">Watch Replay</a>
+        <a href="#/watch/replay?url=/replays/${match.id}.json.gz" class="btn small">Watch Replay</a>
       </div>
     </div>
   `;
diff --git a/web/src/pages/playlists.ts b/web/src/pages/playlists.ts
index fc51a3d..f9aa3d2 100644
--- a/web/src/pages/playlists.ts
+++ b/web/src/pages/playlists.ts
@@ -531,7 +531,7 @@ function addMatchShowMore(container: HTMLElement, remaining: PlaylistMatch[]): v
 }
 
 function watchMatch(matchId: string): void {
-  window.location.hash = `/watch/replay?url=/replays/${matchId}.json`;
+  window.location.hash = `/watch/replay?url=/replays/${matchId}.json.gz`;
 }
 
 function copyEmbedCode(matchId: string): void {