===================================================================
--- original.js
+++ change.js
@@ -58,8 +58,9 @@
 player.y = 2500; // Near bottom
 var zombies = [];
 var bullets = [];
 var score = 0;
+var combo = 0;
 var scoreTxt = new Text2(score.toString(), {
 	size: 150,
 	fill: "#ffffff"
 });
@@ -103,8 +104,9 @@
 		if (bullets[j].y < 0) {
 			// Off screen
 			bullets[j].destroy();
 			bullets.splice(j, 1);
+			combo = 0; // Reset combo multiplier when a bullet misses
 		}
 	}
 	// Check for bullet-zombie collisions
 	for (var b = bullets.length - 1; b >= 0; b--) {
@@ -113,9 +115,10 @@
 				bullets[b].destroy();
 				bullets.splice(b, 1);
 				zombies[z].destroy();
 				zombies.splice(z, 1);
-				score += 1;
+				combo += 1; // Increase combo multiplier on zombie kill
+				score += combo; // Increase score by combo multiplier
 				LK.setScore(score);
 				scoreTxt.setText(score.toString());
 				if (score === 10) {
 					player.destroy();