/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");

/**** 
* Classes
****/ 
var Background = Container.expand(function () {
	var self = Container.call(this);
	var backgroundGraphics = self.attachAsset('background', {
		anchorX: 0,
		anchorY: 0
	});
	return self;
});
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemyShip', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 3;
	self.health = 1;
	self.canShoot = false;
	self.shootTimer = 0;
	self.shootInterval = 120; // 2 seconds at 60fps
	self.update = function () {
		self.y += self.speed;
		if (self.canShoot) {
			self.shootTimer++;
			if (self.shootTimer >= self.shootInterval) {
				self.shootTimer = 0;
				// Create enemy bullet
				var bullet = new EnemyBullet();
				bullet.x = self.x;
				bullet.y = self.y + 40;
				// Calculate direction to player
				var dx = player.x - bullet.x;
				var dy = player.y - bullet.y;
				var distance = Math.sqrt(dx * dx + dy * dy);
				// Normalize direction and set velocity
				bullet.velocityX = dx / distance * bullet.speed;
				bullet.velocityY = dy / distance * bullet.speed;
				enemyBullets.push(bullet);
				game.addChild(bullet);
			}
		}
	};
	return self;
});
var EnemyBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('enemyBullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 8;
	self.velocityX = 0;
	self.velocityY = 8; // Default downward movement
	self.update = function () {
		self.x += self.velocityX;
		self.y += self.velocityY;
	};
	return self;
});
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.attachAsset('playerShip', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.shootCooldown = 0;
	self.shootRate = 20; // Can shoot every 20 frames (50% reduction in firing rate)
	self.update = function () {
		if (self.shootCooldown > 0) {
			self.shootCooldown--;
		}
	};
	self.shoot = function () {
		if (self.shootCooldown <= 0) {
			var bullet = new PlayerBullet();
			bullet.x = self.x;
			bullet.y = self.y - 40;
			// Apply upgrades if score is 50 or higher
			if (LK.getScore() >= 50) {
				bullet.speed = bullet.speed * 1.1; // 10% speed increase
				bullet.scaleX = 1.025; // 2.5% size increase
				bullet.scaleY = 1.025; // 2.5% size increase
			}
			playerBullets.push(bullet);
			game.addChild(bullet);
			self.shootCooldown = self.shootRate;
			LK.getSound('shoot').play();
		}
	};
	return self;
});
var PlayerBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('playerBullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = -17;
	self.update = function () {
		self.y += self.speed;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x000033
});

/**** 
* Game Code
****/ 
// Game variables
var player;
var enemies = [];
var playerBullets = [];
var enemyBullets = [];
var enemySpawnTimer = 0;
var enemySpawnRate = 90; // Start spawning every 1.5 seconds
var dragNode = null;
var gameSpeed = 1;
// Create score display
var scoreTxt = new Text2('Score: 0', {
	size: 60,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0, 0);
scoreTxt.x = 120; // Avoid top-left menu area
scoreTxt.y = 50;
LK.gui.addChild(scoreTxt);
// Create background
var background = new Background();
background.x = 0;
background.y = 0;
game.addChild(background);
// Create player
player = new Player();
player.x = 1024; // Center horizontally
player.y = 2400; // Near bottom of screen
game.addChild(player);
// Start background music
LK.playMusic('bgmusic');
// Game event handlers
game.move = function (x, y, obj) {
	if (dragNode) {
		dragNode.x = Math.max(40, Math.min(2008, x)); // Keep within screen bounds
		dragNode.y = Math.max(40, Math.min(2692, y));
	}
};
game.down = function (x, y, obj) {
	dragNode = player;
	game.move(x, y, obj);
	// Auto-shoot when touching
	player.shoot();
};
game.up = function (x, y, obj) {
	dragNode = null;
};
// Main game update loop
game.update = function () {
	// Update enemy spawn rate based on score
	var score = LK.getScore();
	if (score > 20) {
		enemySpawnRate = 45; // Spawn every 0.75 seconds
	}
	if (score > 50) {
		enemySpawnRate = 30; // Spawn every 0.5 seconds
	}
	// Spawn enemies
	enemySpawnTimer++;
	if (enemySpawnTimer >= enemySpawnRate) {
		enemySpawnTimer = 0;
		var enemy = new Enemy();
		enemy.x = Math.random() * 1800 + 124; // Random x position within screen
		enemy.y = -50; // Start above screen
		// Advanced enemies can shoot back
		if (score > 10) {
			enemy.canShoot = true;
			enemy.shootInterval = 90 + Math.random() * 60; // Vary shoot timing
		}
		if (score > 30) {
			enemy.speed = 4; // Faster enemies
		}
		enemies.push(enemy);
		game.addChild(enemy);
	}
	// Auto-shoot for player when dragging
	if (dragNode === player) {
		player.shoot();
	}
	// Upgrade player bullets when score reaches 50
	if (score >= 50 && !player.bulletsUpgraded) {
		player.bulletsUpgraded = true;
		// Apply upgrades to existing bullets
		for (var upgrade_i = 0; upgrade_i < playerBullets.length; upgrade_i++) {
			var upgradeBullet = playerBullets[upgrade_i];
			upgradeBullet.speed = upgradeBullet.speed * 1.1; // 10% speed increase
			upgradeBullet.scaleX = 1.025; // 2.5% size increase
			upgradeBullet.scaleY = 1.025; // 2.5% size increase
		}
	}
	// Check player bullet collisions with enemies
	for (var i = playerBullets.length - 1; i >= 0; i--) {
		var bullet = playerBullets[i];
		// Remove bullets that go off screen
		if (bullet.y < -50) {
			bullet.destroy();
			playerBullets.splice(i, 1);
			continue;
		}
		// Check collision with enemies
		for (var j = enemies.length - 1; j >= 0; j--) {
			var enemy = enemies[j];
			if (bullet.intersects(enemy)) {
				// Enemy hit
				LK.getSound('enemyHit').play();
				LK.effects.flashObject(enemy, 0xffffff, 200);
				enemy.health--;
				if (enemy.health <= 0) {
					// Enemy destroyed
					LK.setScore(LK.getScore() + 1);
					scoreTxt.setText('Score: ' + LK.getScore());
					enemy.destroy();
					enemies.splice(j, 1);
				}
				bullet.destroy();
				playerBullets.splice(i, 1);
				break;
			}
		}
	}
	// Check enemy bullet collisions with player
	for (var k = enemyBullets.length - 1; k >= 0; k--) {
		var enemyBullet = enemyBullets[k];
		// Remove bullets that go off screen
		if (enemyBullet.y > 2782) {
			enemyBullet.destroy();
			enemyBullets.splice(k, 1);
			continue;
		}
		// Check collision with player
		if (enemyBullet.intersects(player)) {
			// Player hit - game over
			LK.getSound('explosion').play();
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
			return;
		}
	}
	// Check enemy collisions with player
	for (var m = enemies.length - 1; m >= 0; m--) {
		var enemy = enemies[m];
		// Remove enemies that go off screen
		if (enemy.y > 2782) {
			enemy.destroy();
			enemies.splice(m, 1);
			continue;
		}
		// Check collision with player
		if (enemy.intersects(player)) {
			// Player hit by enemy ship - game over
			LK.getSound('explosion').play();
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
			return;
		}
	}
};

===================================================================
--- original.js
+++ change.js
@@ -146,8 +146,10 @@
 player = new Player();
 player.x = 1024; // Center horizontally
 player.y = 2400; // Near bottom of screen
 game.addChild(player);
+// Start background music
+LK.playMusic('bgmusic');
 // Game event handlers
 game.move = function (x, y, obj) {
 	if (dragNode) {
 		dragNode.x = Math.max(40, Math.min(2008, x)); // Keep within screen bounds