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

/**** 
* Classes
****/ 
// Background elements that scrolls to create movement illusion
var BackgroundTile = Container.expand(function () {
	var self = Container.call(this);
	var tileGraphics = self.attachAsset('backgroundTile', {
		anchorX: 0.5,
		anchorY: 0
	});
	self.speed = 2; //{6} // Start with slower speed
	self.update = function () {
		self.y += self.speed;
		// Reset position when it goes out of view
		if (self.y >= 2732) {
			// Calculate the exact position needed for seamless tiling
			// Find the tile that's highest up (lowest y value)
			var highestTile = self;
			var highestY = self.y;
			for (var i = 0; i < backgroundTiles.length; i++) {
				var tile = backgroundTiles[i];
				if (tile !== self && tile.y < highestY) {
					highestTile = tile;
					highestY = tile.y;
				}
			}
			// Position this tile directly above the highest tile
			self.y = highestY - tileGraphics.height;
		}
	};
	return self;
});
// Game variables
// Barrier obstacle
var Barrier = Container.expand(function () {
	var self = Container.call(this);
	var barrierGraphics = self.attachAsset('barrier', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Barrier properties
	self.health = 5;
	self.speed = 2; //{i} // Start with slower speed
	// Last position tracking for collision detection
	self.lastX = 0;
	self.lastY = 0;
	self.lastWasIntersecting = false;
	// Take damage
	self.takeDamage = function () {
		self.health--;
		if (self.health <= 0) {
			LK.getSound('explosion').play();
			LK.setScore(LK.getScore() + 2);
			return true; // Barrier destroyed
		}
		return false; // Barrier still intact
	};
	// Update called every frame
	self.update = function () {
		self.lastX = self.x;
		self.lastY = self.y;
		// Move downward
		self.y += self.speed;
	};
	return self;
});
// Enemy class
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics;
	// Enemy properties
	self.health = 1;
	self.speed = 5;
	self.shootChance = 1; // 1% chance per frame
	self.lane = 0;
	self.type = 'basic'; // basic, shooter, tank
	// Last position tracking for collision detection
	self.lastX = 0;
	self.lastY = 0;
	self.lastWasIntersecting = false;
	// Initialize enemy with type
	self.init = function (type, lane) {
		self.type = type;
		self.lane = lane;
		// Remove previous graphics if exists
		if (enemyGraphics) {
			self.removeChild(enemyGraphics);
		}
		if (type === 'basic') {
			enemyGraphics = self.attachAsset('enemyBasic', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			self.health = 1;
			self.speed = 3; //{P} // Slower starting speed
			self.shootRate = 100; // Shots per second
		} else if (type === 'shooter') {
			enemyGraphics = self.attachAsset('enemyShooter', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			self.health = 1;
			self.speed = 2.5; // Slower starting speed
			self.shootRate = 80; // Moderate fire rate
		} else if (type === 'tank') {
			enemyGraphics = self.attachAsset('enemyTank', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			self.health = 30;
			self.speed = 2; // Slower starting speed
			self.shootRate = 200; // Slow fire rate
		}
	};
	// Shoot method for enemies
	self.shootRate = 100; // Base shoot rate (bullets per frame at 60fps)
	self.shootCooldown = 0;
	self.tryShoot = function () {
		// Create bullet with a rate based on shootRate and normalized for 60fps
		// shootRate is # of frames between shots at 60 FPS
		// Higher shootRate = slower shooting
		// Lower shootRate = faster shooting
		if (Math.random() < 1 / self.shootRate * 60 * LK.deltaTime) {
			var bullet = new EnemyBullet();
			bullet.x = self.x;
			bullet.y = self.y + 60;
			game.addChild(bullet);
			enemyBullets.push(bullet);
		}
	};
	// Take damage
	self.takeDamage = function () {
		self.health--;
		if (self.health <= 0) {
			LK.getSound('explosion').play();
			LK.setScore(LK.getScore() + 1);
			return true; // Enemy destroyed
		}
		return false; // Enemy still alive
	};
	// Update called every frame
	self.update = function () {
		self.lastX = self.x;
		self.lastY = self.y;
		// Move downward
		self.y += self.speed;
		// Update shooting cooldown
		if (self.shootCooldown > 0) {
			self.shootCooldown -= LK.deltaTime;
		}
		// Try to shoot if we're a shooting type
		if ((self.type === 'shooter' || self.type === 'tank' || self.type === 'basic') && self.y > 0) {
			self.tryShoot();
		}
	};
	return self;
});
// Enemy bullet
var EnemyBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('enemyBullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 10;
	// Last position tracking for collision detection
	self.lastX = 0;
	self.lastY = 0;
	self.lastWasIntersecting = false;
	self.update = function () {
		self.lastX = self.x;
		self.lastY = self.y;
		// Move bullet downward using delta time
		var frameRate = 60; // Base frame rate
		var speedMultiplier = LK.deltaTime * frameRate; // Adjust speed based on actual frame time
		self.y += self.speed * speedMultiplier;
	};
	return self;
});
// Lane definitions for positioning
var Lane = Container.expand(function () {
	var self = Container.call(this);
	var laneGraphics = self.attachAsset('lane', {
		anchorX: 0.5,
		anchorY: 0
	});
	return self;
});
// Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.attachAsset('player', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Player properties
	self.currentLane = 1; // 0=left, 1=center, 2=right
	self.shootCooldown = 0;
	self.shootRate = 50; // Configurable shoot rate (bullets per second)
	self.bulletType = 'normal'; // normal, double, triple
	self.powerUpTimer = 0;
	self.isAlive = true;
	self.maxHealth = 3; // Maximum health points
	self.health = self.maxHealth; // Current health
	// Last position tracking for collision detection
	self.lastX = 0;
	self.lastY = 0;
	self.lastWasIntersecting = false;
	// Method to handle damage and health reduction
	self.takeDamage = function () {
		if (!self.isAlive) return; // Don't take damage if already dead
		self.health--; // Subtract health by 1
		// Update health display
		updateHealthDisplay();
		// Flash screen red briefly to indicate damage
		LK.effects.flashScreen(0xff0000, 300);
		// Check if player is dead
		if (self.health <= 0) {
			self.isAlive = false;
			LK.effects.flashScreen(0xff0000, 1000);
			LK.setTimeout(function () {
				LK.showGameOver();
			}, 1000);
		}
		return self.health <= 0; // Return true if player died
	};
	// Movement handling
	self.moveTo = function (laneIndex) {
		if (laneIndex >= 0 && laneIndex <= 2) {
			self.currentLane = laneIndex;
		}
	};
	// Shoot method
	self.shoot = function () {
		// Use the configurable shootRate variable instead of hard-coded value
		if (self.shootCooldown <= 0) {
			LK.getSound('shoot').play();
			if (self.bulletType === 'normal') {
				// Create a single bullet
				var bullet = new PlayerBullet();
				bullet.x = self.x;
				bullet.y = self.y - 60;
				game.addChild(bullet);
				playerBullets.push(bullet);
			} else if (self.bulletType === 'double') {
				// Create two side-by-side bullets
				var bullet1 = new PlayerBullet();
				bullet1.x = self.x - 30;
				bullet1.y = self.y - 60;
				game.addChild(bullet1);
				playerBullets.push(bullet1);
				var bullet2 = new PlayerBullet();
				bullet2.x = self.x + 30;
				bullet2.y = self.y - 60;
				game.addChild(bullet2);
				playerBullets.push(bullet2);
			} else if (self.bulletType === 'triple') {
				// Create three bullets - one forward and two diagonal
				var bulletCenter = new PlayerBullet();
				bulletCenter.x = self.x;
				bulletCenter.y = self.y - 60;
				game.addChild(bulletCenter);
				playerBullets.push(bulletCenter);
				var bulletLeft = new PlayerBullet();
				bulletLeft.x = self.x - 30;
				bulletLeft.y = self.y - 60;
				bulletLeft.angle = -15; // Diagonal left
				game.addChild(bulletLeft);
				playerBullets.push(bulletLeft);
				var bulletRight = new PlayerBullet();
				bulletRight.x = self.x + 30;
				bulletRight.y = self.y - 60;
				bulletRight.angle = 15; // Diagonal right
				game.addChild(bulletRight);
				playerBullets.push(bulletRight);
			}
			// Set cooldown based on the configurable shootRate variable
			self.shootCooldown = self.shootRate / 60; // Normalize to 60 fps
		}
	};
	// Power-up activation
	self.activatePowerUp = function (type) {
		LK.getSound('powerUp').play();
		if (type === 'fastShoot') {
			self.setShootRate(25); // Set faster shooting rate
			self.bulletType = 'normal'; // Keep normal bullet type
		} else {
			self.bulletType = type;
			self.setShootRate(50); // Reset to default rate
		}
		self.powerUpTimer = 600; // 5 seconds at 60fps
	};
	// Method to change the shoot rate
	self.setShootRate = function (rate) {
		if (rate > 0) {
			self.shootRate = rate;
		}
	};
	// Update called every frame
	self.update = function () {
		self.lastX = self.x;
		self.lastY = self.y;
		// Handle cooldowns directly (not converting from frames)
		if (self.shootCooldown > 0) {
			self.shootCooldown -= LK.deltaTime;
		}
		// Power-up timer using delta time
		if (self.powerUpTimer > 0) {
			self.powerUpTimer -= 1; // Decrease by 1 each frame at 60fps
			if (self.powerUpTimer <= 0) {
				self.bulletType = 'normal';
				self.setShootRate(50); // Reset shooting rate to default
			}
		}
		// Auto-shoot
		self.shoot();
	};
	return self;
});
// Player bullet
var PlayerBullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('playerBullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 20;
	self.angle = 0; // 0 = straight, positive/negative for diagonal
	// Last position tracking for collision detection
	self.lastX = 0;
	self.lastY = 0;
	self.lastWasIntersecting = false;
	self.update = function () {
		self.lastX = self.x;
		self.lastY = self.y;
		// Move bullet based on angle using delta time
		var radians = self.angle * (Math.PI / 180);
		var frameRate = 60; // Base frame rate
		var speedMultiplier = LK.deltaTime * frameRate; // Adjust speed based on actual frame time
		self.x += Math.sin(radians) * self.speed * speedMultiplier;
		self.y -= Math.cos(radians) * self.speed * speedMultiplier;
	};
	return self;
});
// Power-up class
var PowerUp = Container.expand(function () {
	var self = Container.call(this);
	// Start with a placeholder that will be replaced in init()
	var powerUpGraphics = self.attachAsset('doublePowerUp', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Power-up properties
	self.type = 'double'; // double, triple
	self.speed = 2; //{2h} // Start with slower speed
	// Last position tracking for collision detection
	self.lastX = 0;
	self.lastY = 0;
	self.lastWasIntersecting = false;
	// Initialize power-up with type
	self.init = function (type) {
		self.type = type;
		// Remove existing graphics
		self.removeChild(powerUpGraphics);
		// Use appropriate image based on power-up type
		if (type === 'double') {
			powerUpGraphics = self.attachAsset('doublePowerUp', {
				anchorX: 0.5,
				anchorY: 0.5
			});
		} else if (type === 'triple') {
			powerUpGraphics = self.attachAsset('triplePowerUp', {
				anchorX: 0.5,
				anchorY: 0.5
			});
		} else if (type === 'fastShoot') {
			powerUpGraphics = self.attachAsset('fastShootPowerUp', {
				anchorX: 0.5,
				anchorY: 0.5
			});
		}
		// Add pulsating animation to the power-up
		function startPulseAnimation() {
			// Grow slightly
			tween(powerUpGraphics, {
				scaleX: 1.1,
				scaleY: 1.1
			}, {
				duration: 800,
				easing: tween.easeInOut,
				onFinish: function onFinish() {
					// Shrink back
					tween(powerUpGraphics, {
						scaleX: 0.9,
						scaleY: 0.9
					}, {
						duration: 800,
						easing: tween.easeInOut,
						onFinish: startPulseAnimation
					});
				}
			});
		}
		// Start the animation
		startPulseAnimation();
	};
	// Update called every frame
	self.update = function () {
		self.lastX = self.x;
		self.lastY = self.y;
		// Move downward
		self.y += self.speed;
	};
	return self;
});

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

/**** 
* Game Code
****/ 
// Add deltaTime calculation if it's not provided by LK engine
// Game variables
// Background
// Sounds
// Power-ups
// Environment and obstacles
// Player, enemies and bullets
// Import tween plugin
if (typeof LK.deltaTime === 'undefined') {
	LK.lastTime = Date.now();
	LK.deltaTime = 1 / 60; // Default to 60fps
	LK.targetFPS = 60;
	// Update deltaTime before each frame
	LK.on('tick', function () {
		var now = Date.now();
		LK.deltaTime = Math.min(0.1, (now - LK.lastTime) / 1000); // Cap at 0.1s to prevent huge jumps
		LK.lastTime = now;
		// Lock to 60fps
		if (LK.deltaTime < 1 / LK.targetFPS) {
			LK.deltaTime = 1 / LK.targetFPS;
		}
	});
}
var player;
var lanes = [];
var lanePositions = [512, 1024, 1536]; // The three lanes X positions
var playerBullets = [];
var enemies = [];
var enemyBullets = [];
var barriers = [];
var powerUps = [];
var backgroundTiles = [];
var healthImages = [];
var gameSpeed = 2; // Start with slower speed
var difficulty = 0.5; // Start with lower difficulty
var spawnTimer = 0;
var barrierTimer = 0;
var powerUpTimer = 0;
var difficultyIncreaseRate = 0.05; // How fast difficulty increases
var maxDifficulty = 6; // Cap on maximum difficulty
// Touch tracking for swipe detection
var touchStartX = null;
var touchStartY = null;
// Initialize the game elements
function initGame() {
	// Play background music with loop
	LK.playMusic('bgMusic', {
		fade: {
			start: 0,
			end: 0.7,
			duration: 1000
		}
	});
	// Set up background
	var bgTileHeight = LK.getAsset('backgroundTile', {}).height;
	var numTilesNeeded = Math.ceil(2732 / bgTileHeight) + 1; // One extra for seamless scrolling
	for (var i = 0; i < numTilesNeeded; i++) {
		var bgTile = new BackgroundTile();
		bgTile.x = 1024; // Center of screen
		bgTile.y = i * bgTileHeight; // Position tiles exactly adjacent to each other
		backgroundTiles.push(bgTile);
		game.addChild(bgTile);
	}
	// Create the lane markers
	for (var i = 0; i < 2; i++) {
		var lane = new Lane();
		lane.x = lanePositions[i] + (lanePositions[1] - lanePositions[0]) / 2; // Position between lanes
		lane.y = 0;
		lane.alpha = 0.3;
		lanes.push(lane);
		game.addChild(lane);
	}
	// Create the player
	player = new Player();
	player.x = lanePositions[1]; // Start in center lane
	player.y = 2732 - 300; // Near bottom of screen
	player.health = player.maxHealth; // Ensure health is set to maximum
	game.addChild(player);
	// Initialize score display
	var scoreBackground = game.addChild(LK.getAsset('scoreBackground', {
		anchorX: 0.5,
		anchorY: 0.5,
		x: 1024,
		y: 80,
		alpha: 0.7
	}));
	var scoreTxt = new Text2('0', {
		size: 60,
		fill: 0xFFFFFF
	});
	scoreTxt.anchor.set(0.5, 0.5);
	scoreTxt.x = 1024;
	scoreTxt.y = 80;
	game.addChild(scoreTxt);
	// Define updateHealthDisplay function in global scope
	function updateHealthDisplay() {
		// Clear existing health images
		for (var i = 0; i < healthImages.length; i++) {
			healthImages[i].destroy();
		}
		healthImages = [];
		// Create new health images based on current health
		for (var i = 0; i < player.health; i++) {
			var heartImage = LK.getAsset('heart', {
				anchorX: 0.5,
				anchorY: 0.5,
				scaleX: 1.5,
				scaleY: 1.5
			});
			// Position hearts at the top right with spacing
			heartImage.x = 1800 - i * 80; // Increased spacing to account for larger hearts
			heartImage.y = 80;
			game.addChild(heartImage);
			healthImages.push(heartImage);
		}
	}
	// Call updateHealthDisplay to initialize health display
	updateHealthDisplay();
	// Update score display every second
	LK.setInterval(function () {
		scoreTxt.setText("SCORE: " + LK.getScore());
	}, 1000);
}
// Spawn a new enemy
function spawnEnemy() {
	var laneIndex = Math.floor(Math.random() * 3);
	var enemyType = 'basic';
	// Determine enemy type based on difficulty
	var typeRoll = Math.random();
	if (difficulty >= 2) {
		if (typeRoll < 0.3) {
			enemyType = 'shooter';
		} else if (typeRoll < 0.4 && difficulty >= 3) {
			enemyType = 'tank';
		}
	}
	var enemy = new Enemy();
	enemy.init(enemyType, laneIndex);
	enemy.x = lanePositions[laneIndex];
	enemy.y = -100;
	game.addChild(enemy);
	enemies.push(enemy);
}
// Spawn a barrier across all lanes
function spawnBarrier() {
	var barrier = new Barrier();
	barrier.x = 1024; // Center of screen
	barrier.y = -100;
	game.addChild(barrier);
	barriers.push(barrier);
}
// Spawn a power-up
function spawnPowerUp() {
	var laneIndex = Math.floor(Math.random() * 3);
	var randomValue = Math.random();
	var powerUpType;
	if (randomValue < 0.33) {
		powerUpType = 'double';
	} else if (randomValue < 0.66) {
		powerUpType = 'triple';
	} else {
		powerUpType = 'fastShoot'; // Add fast shoot power-up type
	}
	var powerUp = new PowerUp();
	powerUp.init(powerUpType);
	powerUp.x = lanePositions[laneIndex];
	powerUp.y = -100;
	game.addChild(powerUp);
	powerUps.push(powerUp);
}
// Increase difficulty over time
function updateDifficulty() {
	// More gradual difficulty increase based on score
	var targetDifficulty = Math.min(maxDifficulty, 0.5 + LK.getScore() / 20);
	// Smooth difficulty transition instead of sudden jumps
	difficulty += (targetDifficulty - difficulty) * difficultyIncreaseRate;
	// Calculate game speed based on smoothed difficulty
	var targetSpeed = 2 + Math.min(difficulty, 4);
	gameSpeed += (targetSpeed - gameSpeed) * 0.05;
	// Update game elements with new speed
	for (var i = 0; i < backgroundTiles.length; i++) {
		backgroundTiles[i].speed = gameSpeed;
	}
	for (var i = 0; i < enemies.length; i++) {
		var speedModifier = enemies[i].type === 'basic' ? 1 : 0;
		var targetEnemySpeed = gameSpeed + speedModifier;
		enemies[i].speed = targetEnemySpeed;
	}
	for (var i = 0; i < barriers.length; i++) {
		barriers[i].speed = gameSpeed;
	}
	for (var i = 0; i < powerUps.length; i++) {
		powerUps[i].speed = gameSpeed;
	}
}
// Handle touch input for lane changing
game.down = function (x, y, obj) {
	// Store touch start position for swipe detection
	game.touchStartX = x;
	game.touchStartY = y;
};
// Handle touch move events for swipe detection
game.move = function (x, y, obj) {
	// Skip if no touch start position is recorded
	if (!game.touchStartX) {
		return;
	}
};
// Handle touch up events for swipe detection
game.up = function (x, y, obj) {
	// Skip if no touch start position is recorded
	if (!game.touchStartX) {
		return;
	}
	// Calculate horizontal distance moved
	var deltaX = x - game.touchStartX;
	var deltaY = y - game.touchStartY;
	// Only process horizontal swipes (ignore vertical)
	if (Math.abs(deltaX) > Math.abs(deltaY) && Math.abs(deltaX) > 50) {
		if (deltaX < 0 && player.currentLane > 0) {
			// Swipe left - move to left lane
			player.moveTo(player.currentLane - 1);
		} else if (deltaX > 0 && player.currentLane < 2) {
			// Swipe right - move to right lane
			player.moveTo(player.currentLane + 1);
		}
	}
	// Reset touch start position
	game.touchStartX = null;
	game.touchStartY = null;
};
// Main update function
game.update = function () {
	// Initialize game on first update
	if (!player) {
		initGame();
		return;
	}
	// Update player position based on current lane
	var targetX = lanePositions[player.currentLane];
	player.x += (targetX - player.x) * 0.2; // Smooth movement
	// Update all game elements
	player.update();
	// Update background tiles
	for (var i = 0; i < backgroundTiles.length; i++) {
		backgroundTiles[i].update();
	}
	// Update and check player bullets
	for (var i = playerBullets.length - 1; i >= 0; i--) {
		var bullet = playerBullets[i];
		bullet.update();
		// Remove bullets that go off screen
		if (bullet.y < -50) {
			bullet.destroy();
			playerBullets.splice(i, 1);
			continue;
		}
		// Check for collisions with enemies
		var hitEnemy = false;
		for (var j = enemies.length - 1; j >= 0; j--) {
			var enemy = enemies[j];
			if (!bullet.lastWasIntersecting && bullet.intersects(enemy)) {
				bullet.lastWasIntersecting = true;
				if (enemy.takeDamage()) {
					enemy.destroy();
					enemies.splice(j, 1);
				}
				hitEnemy = true;
				break;
			}
		}
		// Check for collisions with barriers
		if (!hitEnemy) {
			for (var j = barriers.length - 1; j >= 0; j--) {
				var barrier = barriers[j];
				if (!bullet.lastWasIntersecting && bullet.intersects(barrier)) {
					bullet.lastWasIntersecting = true;
					if (barrier.takeDamage()) {
						barrier.destroy();
						barriers.splice(j, 1);
					}
					hitEnemy = true;
					break;
				}
			}
		}
		// Remove bullet if it hit something
		if (hitEnemy) {
			bullet.destroy();
			playerBullets.splice(i, 1);
		}
	}
	// Update and check enemy bullets
	for (var i = enemyBullets.length - 1; i >= 0; i--) {
		var bullet = enemyBullets[i];
		bullet.update();
		// Remove bullets that go off screen
		if (bullet.y > 2732 + 50) {
			bullet.destroy();
			enemyBullets.splice(i, 1);
			continue;
		}
		// Check for collision with player
		if (!bullet.lastWasIntersecting && bullet.intersects(player) && player.isAlive) {
			bullet.lastWasIntersecting = true;
			// Player hit by enemy bullet - use the takeDamage function
			player.takeDamage();
			bullet.destroy();
			enemyBullets.splice(i, 1);
			break;
		}
	}
	// Update and check enemies
	for (var i = enemies.length - 1; i >= 0; i--) {
		var enemy = enemies[i];
		enemy.update();
		// Remove enemies that go off screen
		if (enemy.y > 2732 + 100) {
			enemy.destroy();
			enemies.splice(i, 1);
			continue;
		}
		// Check for collision with player
		if (!enemy.lastWasIntersecting && enemy.intersects(player) && player.isAlive) {
			enemy.lastWasIntersecting = true;
			// Player hit by enemy - use the takeDamage function
			player.takeDamage();
			break;
		}
	}
	// Update and check barriers
	for (var i = barriers.length - 1; i >= 0; i--) {
		var barrier = barriers[i];
		barrier.update();
		// Remove barriers that go off screen
		if (barrier.y > 2732 + 100) {
			barrier.destroy();
			barriers.splice(i, 1);
			continue;
		}
		// Check for collision with player
		if (!barrier.lastWasIntersecting && barrier.intersects(player) && player.isAlive) {
			barrier.lastWasIntersecting = true;
			// Player hit by barrier - use the takeDamage function
			player.takeDamage();
			break;
		}
	}
	// Update and check power-ups
	for (var i = powerUps.length - 1; i >= 0; i--) {
		var powerUp = powerUps[i];
		powerUp.update();
		// Remove power-ups that go off screen
		if (powerUp.y > 2732 + 100) {
			powerUp.destroy();
			powerUps.splice(i, 1);
			continue;
		}
		// Check for collision with player
		if (!powerUp.lastWasIntersecting && powerUp.intersects(player)) {
			powerUp.lastWasIntersecting = true;
			// Player got power-up
			player.activatePowerUp(powerUp.type);
			// Restore 1 health point when getting a power-up, up to max health
			if (player.health < player.maxHealth) {
				player.health++;
				// Update health display
				updateHealthDisplay();
			}
			powerUp.destroy();
			powerUps.splice(i, 1);
		}
	}
	// Spawn timers - consistent at 60fps
	var frameStep = 60 * LK.deltaTime;
	spawnTimer -= frameStep;
	barrierTimer -= frameStep;
	powerUpTimer -= frameStep;
	// Spawn enemies
	if (spawnTimer <= 0) {
		spawnEnemy();
		// Longer spawn intervals that decrease more slowly with difficulty
		spawnTimer = Math.max(60, 120 - difficulty * 8); // Slower spawn rate at the beginning
	}
	// Spawn barriers occasionally
	if (barrierTimer <= 0 && difficulty >= 1.5) {
		// Lower threshold for barriers
		spawnBarrier();
		barrierTimer = 400; // Every ~6.6 seconds (longer than original)
	}
	// Spawn power-ups occasionally
	if (powerUpTimer <= 0) {
		spawnPowerUp();
		powerUpTimer = 600 + Math.max(0, 300 - difficulty * 50); // Power-ups more frequent as game progresses
	}
	// Update difficulty based on score
	updateDifficulty();
};

===================================================================
--- original.js
+++ change.js