/**** 
* Classes
****/
// Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.createAsset('player', 'Player character', 0.5, 1);
	self.speed = 5;
	self.isJumping = false;
	self.isFlipping = false;
	self.isDashing = false;
	self.jumpHeight = -22;
	self.gravity = 0.5;
	self.velocityY = 0;
	self.jump = function () {
		if (!self.isJumping) {
			self.isJumping = true;
			self.velocityY = self.jumpHeight;
		}
	};
	self.flip = function () {
		if (self.isJumping && !self.isFlipping) {
			self.isFlipping = true;
			playerGraphics.rotation += Math.PI;
		}
	};
	self.dash = function () {
		if (self.isJumping && !self.isDashing) {
			self.isDashing = true;
			self.x += 50;
		}
	};
	self.update = function () {
		if (self.isJumping) {
			self.y += self.velocityY;
			self.velocityY += self.gravity;
			if (self.y > game.height - playerGraphics.height) {
				self.y = game.height - playerGraphics.height;
				self.isJumping = false;
				self.isFlipping = false;
				self.isDashing = false;
				playerGraphics.rotation = 0;
			}
		}
	};
});
// Obstacle class
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var obstacleGraphics = self.createAsset('obstacle', 'Obstacle', 0.5, 1);
	obstacleGraphics.scale.set(0.8);
	self.speed = Obstacle.baseSpeed;
	self.move = function () {
		self.x -= self.speed;
		if (self.x < -obstacleGraphics.width) {
			self.destroy();
		}
	};
});
// Block class
var Block = Container.expand(function () {
	var self = Container.call(this);
	var blockGraphics = self.createAsset('block', 'Harmful block', 0.5, 1);
	blockGraphics.scale.set(0.8);
	self.speed = Obstacle.baseSpeed;
	self.move = function () {
		self.x -= self.speed;
		if (self.x < -blockGraphics.width) {
			self.destroy();
		}
	};
	self.isHarmful = function () {
		// Check if the player's bottom is above the top of the block, which means the player is jumping on it
		var playerBottom = player.y + player.height;
		var blockTop = self.y - blockGraphics.height / 2;
		return playerBottom < blockTop;
	};
});

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

/**** 
* Game Code
****/
// Initialize player
Obstacle.baseSpeed = 3;
Obstacle.increaseSpeed = function () {
	Obstacle.baseSpeed += 1;
};
var player = game.addChild(new Player());
player.x = game.width / 4;
player.y = game.height - 150;
// Initialize obstacles array
var obstacles = [];
// Game tick event
LK.on('tick', function () {
	player.update();
	// Move each obstacle and check for collisions
	for (var i = obstacles.length - 1; i >= 0; i--) {
		obstacles[i].move();
		if (player.intersects(obstacles[i]) && !(obstacles[i] instanceof Block && !obstacles[i].isHarmful())) {
			LK.effects.flashScreen(0xff0000, 500);
			LK.showGameOver();
		}
	}
	// Increase obstacle speed every 25 seconds and make it 10 times faster
	if (LK.ticks % 1500 === 0) {
		Obstacle.baseSpeed = 3;
	}
	// Spawn obstacles and blocks
	if (LK.ticks % 180 === 0) {
		var obstacleType = Math.random() < 0.5 ? Obstacle : Block;
		var obstacle = new obstacleType();
		obstacle.x = game.width;
		obstacle.y = game.height - 100;
		obstacles.push(obstacle);
		game.addChild(obstacle);
	}
});
// Keyboard event listener to make the player jump
game.on('down', function (obj) {
	player.jump();
});
game.on('move', function (obj) {
	var pos = obj.event.getLocalPosition(game);
	if (pos.x > game.width / 2) {
		player.dash();
	} else {
		player.flip();
	}
});
game.on('up', function (obj) {
	// Up event not used in this game
});

===================================================================
--- original.js
+++ change.js
@@ -56,8 +56,27 @@
 			self.destroy();
 		}
 	};
 });
+// Block class
+var Block = Container.expand(function () {
+	var self = Container.call(this);
+	var blockGraphics = self.createAsset('block', 'Harmful block', 0.5, 1);
+	blockGraphics.scale.set(0.8);
+	self.speed = Obstacle.baseSpeed;
+	self.move = function () {
+		self.x -= self.speed;
+		if (self.x < -blockGraphics.width) {
+			self.destroy();
+		}
+	};
+	self.isHarmful = function () {
+		// Check if the player's bottom is above the top of the block, which means the player is jumping on it
+		var playerBottom = player.y + player.height;
+		var blockTop = self.y - blockGraphics.height / 2;
+		return playerBottom < blockTop;
+	};
+});
 
 /**** 
 * Initialize Game
 ****/
@@ -83,20 +102,21 @@
 	player.update();
 	// Move each obstacle and check for collisions
 	for (var i = obstacles.length - 1; i >= 0; i--) {
 		obstacles[i].move();
-		if (player.intersects(obstacles[i])) {
+		if (player.intersects(obstacles[i]) && !(obstacles[i] instanceof Block && !obstacles[i].isHarmful())) {
 			LK.effects.flashScreen(0xff0000, 500);
 			LK.showGameOver();
 		}
 	}
 	// Increase obstacle speed every 25 seconds and make it 10 times faster
 	if (LK.ticks % 1500 === 0) {
 		Obstacle.baseSpeed = 3;
 	}
-	// Spawn obstacles
+	// Spawn obstacles and blocks
 	if (LK.ticks % 180 === 0) {
-		var obstacle = new Obstacle();
+		var obstacleType = Math.random() < 0.5 ? Obstacle : Block;
+		var obstacle = new obstacleType();
 		obstacle.x = game.width;
 		obstacle.y = game.height - 100;
 		obstacles.push(obstacle);
 		game.addChild(obstacle);