/**** 
* Classes
****/
// Hero class
var Hero = Container.expand(function () {
	var self = Container.call(this);
	var heroGraphics = self.createAsset('hero', 'Hero character', 0.5, 0.5);
	self.speed = 5;
	self.jumpPower = -18;
	self.gravity = 0.5;
	self.isJumping = false;
	self.velocityY = 0;
	self.update = function () {
		// Apply gravity
		if (self.isJumping) {
			self.velocityY += self.gravity;
			self.y += self.velocityY;
			if (self.y > game.height - heroGraphics.height / 2) {
				self.isJumping = false;
				self.y = game.height - heroGraphics.height / 2;
			}
		}
	};
	self.jump = function () {
		if (!self.isJumping) {
			self.isJumping = true;
			self.velocityY = self.jumpPower;
		}
	};
});
// Obstacle class
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var obstacleGraphics = self.createAsset('obstacle', 'Obstacle', 0.5, 1);
	self.speed = -6;
	self.move = function () {
		self.x += self.speed;
	};
});

/**** 
* Initialize Game
****/
var game = new LK.Game({
	backgroundColor: 0x000000 // Init game with black background
});

/**** 
* Game Code
****/
// Initialize hero
var hero = game.addChild(new Hero());
hero.x = game.width / 4;
hero.y = game.height - hero.height / 2;

// Initialize obstacles array
var obstacles = [];

// Initialize score
var score = 0;
var scoreTxt = new Text2(score.toString(), {
	size: 150,
	fill: "#ffffff"
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);

// Game tick event
LK.on('tick', function () {
	// Update hero
	hero.update();

	// Move and check obstacles
	for (var i = obstacles.length - 1; i >= 0; i--) {
		obstacles[i].move();
		// Check for collision with hero
		if (hero.intersects(obstacles[i])) {
			// Check if hero jumps on top of the obstacle
			if (hero.y + hero.height / 2 <= obstacles[i].y - obstacles[i].height / 2 && hero.velocityY > 0) {
				// Remove the obstacle if jumped on top
				obstacles[i].destroy();
				obstacles.splice(i, 1);
			} else {
				// Game over if collided from the side
				LK.effects.flashScreen(0xff0000, 1000);
				LK.showGameOver();
				return;
			}
		}
		// Remove off-screen obstacles
		if (obstacles[i].x < -obstacles[i].width) {
			obstacles[i].destroy();
			obstacles.splice(i, 1);
		}
	}

	// Increment score
	score++;
	scoreTxt.setText(score.toString());

	// Add new obstacles
	if (LK.ticks % 120 == 0) {
		var obstacle = new Obstacle();
		obstacle.x = game.width;
		obstacle.y = game.height;
		obstacles.push(obstacle);
		game.addChild(obstacle);
	}
});

// Touch event to make the hero jump
game.on('down', function (obj) {
	hero.jump();
});

===================================================================
--- original.js
+++ change.js
@@ -74,11 +74,19 @@
 	for (var i = obstacles.length - 1; i >= 0; i--) {
 		obstacles[i].move();
 		// Check for collision with hero
 		if (hero.intersects(obstacles[i])) {
-			LK.effects.flashScreen(0xff0000, 1000);
-			LK.showGameOver();
-			return;
+			// Check if hero jumps on top of the obstacle
+			if (hero.y + hero.height / 2 <= obstacles[i].y - obstacles[i].height / 2 && hero.velocityY > 0) {
+				// Remove the obstacle if jumped on top
+				obstacles[i].destroy();
+				obstacles.splice(i, 1);
+			} else {
+				// Game over if collided from the side
+				LK.effects.flashScreen(0xff0000, 1000);
+				LK.showGameOver();
+				return;
+			}
 		}
 		// Remove off-screen obstacles
 		if (obstacles[i].x < -obstacles[i].width) {
 			obstacles[i].destroy();