/**** 
* Classes
****/ 
var ControlButton = Container.expand(function (type) {
	var self = Container.call(this);
	self.buttonType = type;
	self.isPressed = false;
	var buttonGraphics;
	if (type === 'jump') {
		buttonGraphics = self.attachAsset('jumpButton', {
			anchorX: 0.5,
			anchorY: 0.5
		});
	} else {
		buttonGraphics = self.attachAsset(type === 'left' ? 'leftButton' : 'rightButton', {
			anchorX: 0.5,
			anchorY: 0.5
		});
	}
	self.down = function (x, y, obj) {
		self.isPressed = true;
		buttonGraphics.alpha = 0.7;
	};
	self.up = function (x, y, obj) {
		self.isPressed = false;
		buttonGraphics.alpha = 1.0;
	};
	return self;
});
var Platform = Container.expand(function (width, height) {
	var self = Container.call(this);
	self.platformWidth = width || 300;
	self.platformHeight = height || 40;
	var platformGraphics = self.attachAsset('platform', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: self.platformWidth / 300,
		scaleY: self.platformHeight / 40
	});
	return self;
});
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.attachAsset('player', {
		anchorX: 0.5,
		anchorY: 1.0
	});
	self.velocityX = 0;
	self.velocityY = 0;
	self.speed = 8;
	self.jumpPower = 50;
	self.gravity = 0.8;
	self.onGround = false;
	self.maxFallSpeed = 15;
	self.moveLeft = function () {
		self.velocityX = -self.speed;
	};
	self.moveRight = function () {
		self.velocityX = self.speed;
	};
	self.jump = function () {
		if (self.onGround) {
			self.velocityY = -self.jumpPower;
			self.onGround = false;
		}
	};
	self.stopHorizontalMovement = function () {
		self.velocityX = 0;
	};
	self.update = function () {
		// Apply gravity
		self.velocityY += self.gravity;
		// Limit fall speed
		if (self.velocityY > self.maxFallSpeed) {
			self.velocityY = self.maxFallSpeed;
		}
		// Update position
		self.x += self.velocityX;
		self.y += self.velocityY;
		// Keep player within screen bounds horizontally
		if (self.x < 60) {
			self.x = 60;
		}
		if (self.x > 1988) {
			self.x = 1988;
		}
		// Reset onGround flag
		self.onGround = false;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x87ceeb
});

/**** 
* Game Code
****/ 
var player = game.addChild(new Player());
player.x = 1024;
player.y = 2500;
var platforms = [];
var ground = game.addChild(LK.getAsset('ground', {
	anchorX: 0.5,
	anchorY: 1.0
}));
ground.x = 1024;
ground.y = 2732;
// Create platforms
var platformData = [{
	x: 400,
	y: 2400,
	width: 200
}, {
	x: 800,
	y: 2200,
	width: 250
}, {
	x: 1200,
	y: 2000,
	width: 200
}, {
	x: 600,
	y: 1800,
	width: 300
}, {
	x: 1400,
	y: 1600,
	width: 200
}, {
	x: 300,
	y: 1400,
	width: 250
}, {
	x: 1000,
	y: 1200,
	width: 300
}, {
	x: 1600,
	y: 1000,
	width: 200
}];
for (var i = 0; i < platformData.length; i++) {
	var platformInfo = platformData[i];
	var platform = game.addChild(new Platform(platformInfo.width));
	platform.x = platformInfo.x;
	platform.y = platformInfo.y;
	platforms.push(platform);
}
// Control buttons
var leftButton = LK.gui.bottomLeft.addChild(new ControlButton('left'));
leftButton.x = 80;
leftButton.y = -80;
var rightButton = LK.gui.bottomLeft.addChild(new ControlButton('right'));
rightButton.x = 220;
rightButton.y = -80;
var jumpButton = LK.gui.bottomRight.addChild(new ControlButton('jump'));
jumpButton.x = -80;
jumpButton.y = -80;
// Control button labels
var leftLabel = new Text2('←', {
	size: 60,
	fill: 0xFFFFFF
});
leftLabel.anchor.set(0.5, 0.5);
leftButton.addChild(leftLabel);
var rightLabel = new Text2('→', {
	size: 60,
	fill: 0xFFFFFF
});
rightLabel.anchor.set(0.5, 0.5);
rightButton.addChild(rightLabel);
var jumpLabel = new Text2('↑', {
	size: 60,
	fill: 0xFFFFFF
});
jumpLabel.anchor.set(0.5, 0.5);
jumpButton.addChild(jumpLabel);
function checkCollisions() {
	var playerBottom = player.y;
	var playerTop = player.y - 120;
	var playerLeft = player.x - 60;
	var playerRight = player.x + 60;
	// Check ground collision
	if (playerBottom >= ground.y - 50) {
		if (player.velocityY > 0) {
			player.y = ground.y - 50;
			player.velocityY = 0;
			player.onGround = true;
		}
	}
	// Check platform collisions
	for (var i = 0; i < platforms.length; i++) {
		var platform = platforms[i];
		var platformLeft = platform.x - platform.platformWidth / 2;
		var platformRight = platform.x + platform.platformWidth / 2;
		var platformTop = platform.y - platform.platformHeight / 2;
		var platformBottom = platform.y + platform.platformHeight / 2;
		// Check if player is horizontally aligned with platform
		if (playerRight > platformLeft && playerLeft < platformRight) {
			// Check if player is falling onto platform from above
			if (player.velocityY > 0 && playerBottom >= platformTop && playerTop < platformTop) {
				player.y = platformTop;
				player.velocityY = 0;
				player.onGround = true;
			}
		}
	}
}
game.update = function () {
	// Check collisions first to set onGround flag
	checkCollisions();
	// Handle input
	if (leftButton.isPressed) {
		player.moveLeft();
	} else if (rightButton.isPressed) {
		player.moveRight();
	} else {
		player.stopHorizontalMovement();
	}
	if (jumpButton.isPressed) {
		player.jump();
	}
	// Check if player fell off screen
	if (player.y > 2800) {
		// Reset player position
		player.x = 1024;
		player.y = 2500;
		player.velocityX = 0;
		player.velocityY = 0;
	}
};

===================================================================
--- original.js
+++ change.js
@@ -211,8 +211,10 @@
 		}
 	}
 }
 game.update = function () {
+	// Check collisions first to set onGround flag
+	checkCollisions();
 	// Handle input
 	if (leftButton.isPressed) {
 		player.moveLeft();
 	} else if (rightButton.isPressed) {
@@ -222,10 +224,8 @@
 	}
 	if (jumpButton.isPressed) {
 		player.jump();
 	}
-	// Check collisions
-	checkCollisions();
 	// Check if player fell off screen
 	if (player.y > 2800) {
 		// Reset player position
 		player.x = 1024;