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

/**** 
* Classes
****/ 
// Bullet class
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	var sprite = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = 20;
	self.dx = 0;
	self.dy = 0;
	self.speed = 38;
	self.isPlayer = false;
	self.lifetime = 60; // frames
	self.update = function () {
		self.x += self.dx * self.speed;
		self.y += self.dy * self.speed;
		self.lifetime--;
	};
	return self;
});
// Enemy class
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var sprite = self.attachAsset('enemy', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = 55;
	self.speed = 7 + Math.random() * 3;
	self.shootCooldown = 0;
	self.shootDelay = 60 + Math.floor(Math.random() * 30);
	self.targetX = 0;
	self.targetY = 0;
	self.isAlive = true;
	self.aiTimer = 0;
	self.update = function () {
		if (countdownActive) return;
		if (!self.isAlive) return;
		// AI: Move toward player, avoid obstacles
		if (self.aiTimer <= 0) {
			// Pick a new target near player, with some randomness
			var px = player.x + (Math.random() - 0.5) * 300;
			var py = player.y + (Math.random() - 0.5) * 300;
			// Clamp to arena
			px = Math.max(arena.x + 100, Math.min(arena.x + arena.w - 100, px));
			py = Math.max(arena.y + 100, Math.min(arena.y + arena.h - 100, py));
			self.targetX = px;
			self.targetY = py;
			self.aiTimer = 30 + Math.floor(Math.random() * 30);
		} else {
			self.aiTimer--;
		}
		// Move toward target
		var dx = self.targetX - self.x;
		var dy = self.targetY - self.y;
		var mag = Math.sqrt(dx * dx + dy * dy);
		if (mag > 10) {
			var mx = dx / mag * self.speed;
			var my = dy / mag * self.speed;
			// Try to move, but avoid obstacles
			var nx = self.x + mx;
			var ny = self.y + my;
			var blocked = false;
			for (var i = 0; i < obstacles.length; ++i) {
				if (rectCircleCollide(obstacles[i], nx, ny, self.radius)) {
					blocked = true;
					break;
				}
			}
			if (!blocked) {
				self.x = nx;
				self.y = ny;
			}
		}
		// Shoot at player if in line of sight
		if (self.shootCooldown > 0) self.shootCooldown--;else {
			if (canSee(self.x, self.y, player.x, player.y)) {
				var ddx = player.x - self.x;
				var ddy = player.y - self.y;
				var dmag = Math.sqrt(ddx * ddx + ddy * ddy);
				if (dmag > 0) {
					var bullet = new Bullet();
					bullet.x = self.x + ddx / dmag * (self.radius + 30);
					bullet.y = self.y + ddy / dmag * (self.radius + 30);
					bullet.dx = ddx / dmag;
					bullet.dy = ddy / dmag;
					bullet.isPlayer = false;
					bullets.push(bullet);
					game.addChild(bullet);
					self.shootCooldown = self.shootDelay;
				}
			}
		}
	};
	// Take damage
	self.hit = function () {
		if (!self.isAlive) return;
		self.isAlive = false;
		tween(sprite, {
			alpha: 0
		}, {
			duration: 200,
			onFinish: function onFinish() {
				self.destroy();
			}
		});
	};
	return self;
});
// Obstacle class
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var sprite = self.attachAsset('obstacle', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.width = sprite.width;
	self.height = sprite.height;
	return self;
});
// Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	var sprite = self.attachAsset('player', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = 60;
	self.speed = 18;
	self.shootCooldown = 0;
	self.shootDelay = 18; // frames
	self.isAlive = true;
	self.invincible = 0; // frames left of invincibility
	// For touch drag
	self.down = function (x, y, obj) {};
	self.up = function (x, y, obj) {};
	// For powerup
	self.powered = false;
	self.powerTimer = 0;
	self.update = function () {
		if (!self.isAlive) return;
		if (self.invincible > 0) self.invincible--;
		if (self.powered) {
			self.powerTimer--;
			if (self.powerTimer <= 0) {
				self.powered = false;
				sprite.tint = 0x2a6cff;
			}
		}
		if (self.shootCooldown > 0) self.shootCooldown--;
	};
	// Shoot a bullet in direction (dx, dy)
	self.shoot = function (dx, dy) {
		if (!self.isAlive) return;
		if (self.shootCooldown > 0) return;
		var mag = Math.sqrt(dx * dx + dy * dy);
		if (mag < 0.1) return;
		var bullet = new Bullet();
		bullet.x = self.x + dx / mag * (self.radius + 30);
		bullet.y = self.y + dy / mag * (self.radius + 30);
		bullet.dx = dx / mag;
		bullet.dy = dy / mag;
		bullet.isPlayer = true;
		bullets.push(bullet);
		game.addChild(bullet);
		self.shootCooldown = self.powered ? 5 : self.shootDelay;
	};
	// Take damage
	self.hit = function () {
		if (self.invincible > 0 || !self.isAlive) return;
		self.isAlive = false;
		tween(sprite, {
			alpha: 0
		}, {
			duration: 400,
			onFinish: function onFinish() {
				LK.effects.flashScreen(0xff0000, 800);
				LK.showGameOver();
			}
		});
	};
	// Powerup
	self.powerup = function () {
		self.powered = true;
		self.powerTimer = 360; // 6 seconds
		sprite.tint = 0x3be14a;
	};
	return self;
});
// Powerup class
var Powerup = Container.expand(function () {
	var self = Container.call(this);
	var sprite = self.attachAsset('powerup', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = 30;
	self.type = 'rapid';
	self.lifetime = 600; // 10 seconds
	self.update = function () {
		self.lifetime--;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x181818
});

/**** 
* Game Code
****/ 
// Arena bounds
// Player character: blue box
// Enemy: red box
// Bullet: yellow ellipse
// Obstacle: gray box
// Powerup: green ellipse
var arena = {
	x: 180,
	y: 300,
	w: 2048 - 360,
	h: 2732 - 600
};
// Game state
var player;
var enemies = [];
var bullets = [];
var obstacles = [];
var powerups = [];
var round = 1;
var roundActive = false;
var roundTimer = 0;
var spawnTimer = 0;
var dragNode = null;
var lastTouch = {
	x: 0,
	y: 0
};
var scoreTxt;
var roundTxt;
var powerupTxt;
var gameOver = false;
// Countdown state
var countdownActive = false;
var countdownValue = 0;
var countdownTxt = null;
var countdownTimeout = null;
// GUI
scoreTxt = new Text2('Score: 0', {
	size: 90,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
roundTxt = new Text2('Round 1', {
	size: 70,
	fill: 0xFFCC00
});
roundTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(roundTxt);
powerupTxt = new Text2('', {
	size: 60,
	fill: 0x3BE14A
});
powerupTxt.anchor.set(0.5, 0);
LK.gui.bottom.addChild(powerupTxt);
// Place obstacles
function setupObstacles() {
	for (var i = 0; i < obstacles.length; ++i) obstacles[i].destroy();
	obstacles = [];
	// Place 4-6 obstacles randomly
	var obsCount = 4 + Math.floor(Math.random() * 3);
	for (var i = 0; i < obsCount; ++i) {
		var obs = new Obstacle();
		obs.x = arena.x + 200 + Math.random() * (arena.w - 400);
		obs.y = arena.y + 200 + Math.random() * (arena.h - 400);
		if (i % 2 == 0) obs.rotation = Math.PI / 2;
		obstacles.push(obs);
		game.addChild(obs);
	}
}
// Place player
function setupPlayer() {
	if (player) player.destroy();
	player = new Player();
	player.x = arena.x + arena.w / 2;
	player.y = arena.y + arena.h - 200;
	game.addChild(player);
}
// Place enemies
function setupEnemies(n) {
	for (var i = 0; i < enemies.length; ++i) enemies[i].destroy();
	enemies = [];
	for (var i = 0; i < n; ++i) {
		var e = new Enemy();
		// Spawn at top or sides
		var edge = Math.floor(Math.random() * 4);
		if (edge == 0) {
			// top
			e.x = arena.x + 200 + Math.random() * (arena.w - 400);
			e.y = arena.y + 120;
		} else if (edge == 1) {
			// left
			e.x = arena.x + 120;
			e.y = arena.y + 200 + Math.random() * (arena.h - 400);
		} else if (edge == 2) {
			// right
			e.x = arena.x + arena.w - 120;
			e.y = arena.y + 200 + Math.random() * (arena.h - 400);
		} else {
			// bottom
			e.x = arena.x + 200 + Math.random() * (arena.w - 400);
			e.y = arena.y + arena.h - 120;
		}
		enemies.push(e);
		game.addChild(e);
	}
}
// Place powerup
function spawnPowerup() {
	var p = new Powerup();
	p.x = arena.x + 150 + Math.random() * (arena.w - 300);
	p.y = arena.y + 150 + Math.random() * (arena.h - 300);
	powerups.push(p);
	game.addChild(p);
}
// Start round
function startRound() {
	// Start countdown before round actually starts
	roundActive = false;
	countdownActive = true;
	countdownValue = 3;
	// Remove previous countdown text if exists
	if (countdownTxt) {
		countdownTxt.destroy();
		countdownTxt = null;
	}
	countdownTxt = new Text2('3', {
		size: 300,
		fill: 0xFFCC00
	});
	countdownTxt.anchor.set(0.5, 0.5);
	LK.gui.center.addChild(countdownTxt);
	// Setup everything for the round, but don't activate yet
	roundTimer = 0;
	spawnTimer = 0;
	setupObstacles();
	setupPlayer();
	setupEnemies(2 + round);
	for (var i = 0; i < bullets.length; ++i) bullets[i].destroy();
	bullets = [];
	for (var i = 0; i < powerups.length; ++i) powerups[i].destroy();
	powerups = [];
	roundTxt.setText('Round ' + round);
	powerupTxt.setText('');
	LK.setScore(LK.getScore());
	scoreTxt.setText('Score: ' + LK.getScore());
	// Start countdown timer
	function doCountdown() {
		if (!countdownActive) return;
		countdownValue--;
		if (countdownValue > 0) {
			countdownTxt.setText(countdownValue + '');
			countdownTimeout = LK.setTimeout(doCountdown, 800);
		} else {
			// Go!
			countdownTxt.setText('GO!');
			countdownTimeout = LK.setTimeout(function () {
				if (countdownTxt) {
					countdownTxt.destroy();
					countdownTxt = null;
				}
				countdownActive = false;
				roundActive = true;
			}, 600);
		}
	}
	countdownTimeout = LK.setTimeout(doCountdown, 800);
}
// Utility: circle-rectangle collision
function rectCircleCollide(obs, cx, cy, cr) {
	var rx = obs.x - obs.width / 2;
	var ry = obs.y - obs.height / 2;
	var rw = obs.width;
	var rh = obs.height;
	var closestX = Math.max(rx, Math.min(cx, rx + rw));
	var closestY = Math.max(ry, Math.min(cy, ry + rh));
	var dx = cx - closestX;
	var dy = cy - closestY;
	return dx * dx + dy * dy < cr * cr;
}
// Utility: circle-circle collision
function circleCollide(a, b) {
	var dx = a.x - b.x;
	var dy = a.y - b.y;
	var r = (a.radius || 0) + (b.radius || 0);
	return dx * dx + dy * dy < r * r;
}
// Utility: line of sight (returns true if no obstacle blocks)
function canSee(x1, y1, x2, y2) {
	for (var i = 0; i < obstacles.length; ++i) {
		if (lineRectIntersect(x1, y1, x2, y2, obstacles[i])) return false;
	}
	return true;
}
// Utility: line-rectangle intersection
function lineRectIntersect(x1, y1, x2, y2, obs) {
	var rx = obs.x - obs.width / 2;
	var ry = obs.y - obs.height / 2;
	var rw = obs.width;
	var rh = obs.height;
	// Check each side
	if (lineLineIntersect(x1, y1, x2, y2, rx, ry, rx + rw, ry)) return true;
	if (lineLineIntersect(x1, y1, x2, y2, rx + rw, ry, rx + rw, ry + rh)) return true;
	if (lineLineIntersect(x1, y1, x2, y2, rx + rw, ry + rh, rx, ry + rh)) return true;
	if (lineLineIntersect(x1, y1, x2, y2, rx, ry + rh, rx, ry)) return true;
	return false;
}
// Utility: line-line intersection
function lineLineIntersect(x1, y1, x2, y2, x3, y3, x4, y4) {
	var denom = (y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1);
	if (denom == 0) return false;
	var ua = ((x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3)) / denom;
	var ub = ((x2 - x1) * (y1 - y3) - (y2 - y1) * (x1 - x3)) / denom;
	return ua >= 0 && ua <= 1 && ub >= 0 && ub <= 1;
}
// Clamp player inside arena and avoid obstacles
function clampPlayer(px, py) {
	// Clamp to arena
	px = Math.max(arena.x + player.radius, Math.min(arena.x + arena.w - player.radius, px));
	py = Math.max(arena.y + player.radius, Math.min(arena.y + arena.h - player.radius, py));
	// Avoid obstacles
	for (var i = 0; i < obstacles.length; ++i) {
		if (rectCircleCollide(obstacles[i], px, py, player.radius)) {
			// Push out
			var ox = obstacles[i].x;
			var oy = obstacles[i].y;
			var dx = px - ox;
			var dy = py - oy;
			var mag = Math.sqrt(dx * dx + dy * dy);
			if (mag > 0) {
				px = ox + dx / mag * (obstacles[i].width / 2 + player.radius + 2);
				py = oy + dy / mag * (obstacles[i].height / 2 + player.radius + 2);
			}
		}
	}
	return {
		x: px,
		y: py
	};
}
// Touch controls: drag to move, tap to shoot
game.down = function (x, y, obj) {
	if (countdownActive) return;
	if (!player.isAlive) return;
	// If touch is near player, start drag
	var dx = x - player.x;
	var dy = y - player.y;
	if (dx * dx + dy * dy < player.radius * player.radius * 2) {
		dragNode = player;
	} else {
		// Else, shoot toward touch
		var dirx = x - player.x;
		var diry = y - player.y;
		player.shoot(dirx, diry);
	}
	lastTouch.x = x;
	lastTouch.y = y;
};
game.move = function (x, y, obj) {
	if (countdownActive) return;
	if (!player.isAlive) return;
	if (dragNode === player) {
		// Move player toward touch, but clamp
		var dx = x - player.x;
		var dy = y - player.y;
		var mag = Math.sqrt(dx * dx + dy * dy);
		if (mag > 0) {
			var step = Math.min(player.speed, mag);
			var nx = player.x + dx / mag * step;
			var ny = player.y + dy / mag * step;
			var clamped = clampPlayer(nx, ny);
			player.x = clamped.x;
			player.y = clamped.y;
		}
		lastTouch.x = x;
		lastTouch.y = y;
	}
};
game.up = function (x, y, obj) {
	dragNode = null;
};
// Main update loop
game.update = function () {
	// If countdown is active, pause gameplay updates
	if (countdownActive) {
		return;
	}
	if (!roundActive) {
		startRound();
		return;
	}
	if (!player.isAlive) return;
	// Update player
	player.update();
	// Update enemies
	for (var i = enemies.length - 1; i >= 0; --i) {
		var e = enemies[i];
		e.update();
		// If dead, remove
		if (!e.isAlive && e.alpha <= 0) {
			e.destroy();
			enemies.splice(i, 1);
			LK.setScore(LK.getScore() + 1);
			scoreTxt.setText('Score: ' + LK.getScore());
		}
	}
	// Update bullets
	for (var i = bullets.length - 1; i >= 0; --i) {
		var b = bullets[i];
		b.update();
		// Remove if out of bounds or expired
		if (b.x < arena.x - 100 || b.x > arena.x + arena.w + 100 || b.y < arena.y - 100 || b.y > arena.y + arena.h + 100 || b.lifetime <= 0) {
			b.destroy();
			bullets.splice(i, 1);
			continue;
		}
		// Collide with obstacles
		var hitObs = false;
		for (var j = 0; j < obstacles.length; ++j) {
			if (rectCircleCollide(obstacles[j], b.x, b.y, b.radius)) {
				hitObs = true;
				break;
			}
		}
		if (hitObs) {
			b.destroy();
			bullets.splice(i, 1);
			continue;
		}
		// Collide with enemies (if player bullet)
		if (b.isPlayer) {
			for (var j = 0; j < enemies.length; ++j) {
				if (enemies[j].isAlive && circleCollide(b, enemies[j])) {
					enemies[j].hit();
					b.destroy();
					bullets.splice(i, 1);
					break;
				}
			}
		} else {
			// Collide with player
			if (player.isAlive && circleCollide(b, player)) {
				if (player.invincible <= 0) {
					player.hit();
				}
				b.destroy();
				bullets.splice(i, 1);
			}
		}
	}
	// Update powerups
	for (var i = powerups.length - 1; i >= 0; --i) {
		var p = powerups[i];
		p.update();
		if (p.lifetime <= 0) {
			p.destroy();
			powerups.splice(i, 1);
			continue;
		}
		// Collide with player
		if (player.isAlive && circleCollide(p, player)) {
			player.powerup();
			powerupTxt.setText('Rapid Fire!');
			p.destroy();
			powerups.splice(i, 1);
		}
	}
	// Spawn powerup occasionally
	if (LK.ticks % 600 == 0 && powerups.length == 0) {
		spawnPowerup();
	}
	// End round if all enemies dead
	if (enemies.length == 0) {
		roundActive = false;
		round++;
		LK.setTimeout(function () {
			startRound();
		}, 1200);
	}
};
// Initial round
startRound();

===================================================================
--- original.js
+++ change.js
@@ -41,8 +41,9 @@
 	self.targetY = 0;
 	self.isAlive = true;
 	self.aiTimer = 0;
 	self.update = function () {
+		if (countdownActive) return;
 		if (!self.isAlive) return;
 		// AI: Move toward player, avoid obstacles
 		if (self.aiTimer <= 0) {
 			// Pick a new target near player, with some randomness
@@ -219,14 +220,14 @@
 
 /**** 
 * Game Code
 ****/ 
-// Powerup: green ellipse
-// Obstacle: gray box
-// Bullet: yellow ellipse
-// Enemy: red box
-// Player character: blue box
 // Arena bounds
+// Player character: blue box
+// Enemy: red box
+// Bullet: yellow ellipse
+// Obstacle: gray box
+// Powerup: green ellipse
 var arena = {
 	x: 180,
 	y: 300,
 	w: 2048 - 360,