var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var obstacleGraphics = XS.getAsset('obstacle', 'Obstacle', .5, 1);
	obstacleGraphics.y += 50;
	self.addChild(obstacleGraphics);
});
var OverlayElement = Container.expand(function () {
	var self = Container.call(this);
	var overlayGraphics = XS.getAsset('overlay', 'Overlay Element', .5, 1);
	self.addChild(overlayGraphics);
	self.alpha = 0;
	self.flashed = false;
	self.flash = function (color, duration) {
		overlayGraphics.tint = color;
		self.alpha = 1;
		var fadeOutInterval = XS.setInterval(function () {
			self.alpha -= 0.02;
			if (self.alpha <= 0) {
				XS.clearInterval(fadeOutInterval);
			}
		}, duration / 50);
	};
});
var ExitDoor = Container.expand(function () {
	var self = Container.call(this);
	var backgroundElement = XS.getAsset('backgroundElement1', 'Background Element 1', .5, .5);
	backgroundElement.y -= 760;
	self.addChild(backgroundElement);
	var backgroundElement2 = XS.getAsset('backgroundElement2', 'Background Element 2', .5, .5);
	backgroundElement2.y -= 760;
	backgroundElement2.blendMode = 1;
	self.addChild(backgroundElement2);
	var doorGraphics = XS.getAsset('exitDoor', 'Exit Door', .5, 1);
	self.addChild(doorGraphics);
	self.rotationSpeed1 = 0.005 * 0.25;
	self.rotationSpeed2 = 0.007 * 0.25;
	self.rotate = function () {
		backgroundElement.rotation += self.rotationSpeed1;
		backgroundElement2.rotation -= self.rotationSpeed2;
	};
});
var EnemySpawnIndicator = Container.expand(function () {
	var self = Container.call(this);
	var spawnIndicatorGraphics = XS.getAsset('spawnIndicator', 'Enemy Spawn Indicator', .5, .5);
	spawnIndicatorGraphics.alpha = 0.5;
	self.addChild(spawnIndicatorGraphics);
});
var ExplosionParticle = Container.expand(function () {
	var self = Container.call(this);
	var particleGraphics = XS.getAsset('particle', 'Explosion particle', .5, .5);
	particleGraphics.scale.set(Math.random() * .5 + .5);
	particleGraphics.y -= 150;
	particleGraphics.blendMode = 3;
	self.addChild(particleGraphics);
	self.dx = (Math.random() - 0.5) * 10;
	self.dy = (Math.random() - 0.5) * 7;
	self.move = function () {
		self.x += self.dx;
		self.y += self.dy;
		self.alpha -= 0.02;
		particleGraphics.scale.x *= 0.98;
		particleGraphics.scale.y *= 0.98;
		self.dx *= 0.98;
		self.dy *= 0.98;
		if (self.alpha <= 0) {
			self.destroy();
		}
	};
});
var HealthBar = Container.expand(function () {
	var self = Container.call(this);
	var healthBarGraphics = XS.getAsset('healthBar', 'Health Bar', .5, 1);
	self.addChild(healthBarGraphics);
	self.setTint = function (tint) {
		healthBarGraphics.tint = tint;
	};
	self.setTint(0x00FF00);
	self.updateHealth = function (health) {
		self.scale.x = health / 100;
	};
});
var TargetIndicator = Container.expand(function () {
	var self = Container.call(this);
	var targetGraphics = XS.getAsset('target', 'Target Indicator', .5, .5);
	targetGraphics.alpha = 0.5;
	targetGraphics.y -= 30;
	self.addChild(targetGraphics);
});
var Player = Container.expand(function () {
	var self = Container.call(this);
	self.health = 100;
	self.findNearestEnemy = function (enemies) {
		var nearestEnemy = null;
		var nearestDistance = Infinity;
		for (var i = 0; i < enemies.length; i++) {
			var dx = enemies[i].x - self.x;
			var dy = enemies[i].y - self.y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			if (distance < nearestDistance && !self.parent.lineIntersectsObstacle(self.x, self.y, enemies[i].x, enemies[i].y)) {
				nearestDistance = distance;
				nearestEnemy = enemies[i];
			}
		}
		return nearestEnemy;
	};
	var playerShadow = XS.getAsset('playerShadow', 'Player shadow', .5, .8);
	playerShadow.alpha = 0.3;
	self.addChild(playerShadow);
	var playerGraphics = XS.getAsset('player', 'Player character', .5, 1);
	self.addChild(playerGraphics);
	var healthBar = new HealthBar();
	healthBar.y = -playerGraphics.height;
	self.addChild(healthBar);
	self.healthBar = healthBar;
	self.targetX = 2048 / 2;
	self.targetY = 2732 / 2;
	self.speed = 5;
	self.lastShot = 0;
	self.move = function () {
		var dx = self.targetX - self.x;
		var dy = self.targetY - self.y;
		var distance = Math.sqrt(dx * dx + dy * dy);
		if (distance > self.speed) {
			self.x += dx / distance * self.speed;
			self.y += dy / distance * self.speed;
			self.healthBar.updateHealth(self.health);
			return true;
		}
		self.healthBar.updateHealth(self.health);
		return false;
	};
	self.setTarget = function (x, y) {
		self.targetX = x;
		self.targetY = y;
	};
	self.shoot = function (enemies) {
		var bullet = new Bullet();
		bullet.x = self.x;
		bullet.y = self.y;
		var nearestEnemy = self.findNearestEnemy(enemies);
		if (nearestEnemy) {
			var dx = nearestEnemy.x - self.x;
			var dy = nearestEnemy.y - self.y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			bullet.dx = dx / distance;
			bullet.dy = dy / distance;
		}
		return bullet;
	};
});
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	self.alpha = 0;
	self.dx = 0;
	self.dy = 0;
	self.fadeRedTint = function () {
		if (self.fadeOutRedTint > 0) {
			enemyGraphics.tint = 0xff0000 + (0xffffff - 0xff0000) * (10 - self.fadeOutRedTint) / 10;
			if (--self.fadeOutRedTint <= 0) {
				enemyGraphics.tint = 0xFFFFFF;
			}
		}
	};
	self.health = 100;
	self.animateIn = function () {
		self.fadeInTicks = 50;
	};
	var enemyShadow = XS.getAsset('enemyShadow', 'Enemy shadow', .5, .8);
	enemyShadow.alpha = 0.3;
	self.addChild(enemyShadow);
	var enemyGraphics = XS.getAsset('enemy', 'Enemy character', .5, 1);
	self.addChild(enemyGraphics);
	var healthBar = new HealthBar();
	healthBar.setTint(0xFF0000);
	healthBar.y = -enemyGraphics.height;
	self.addChild(healthBar);
	self.healthBar = healthBar;
	self.healthBar.updateHealth(self.health);
	self.move = function () {
		self.fadeRedTint();
		if (self.fadeInTicks > 0) {
			self.alpha += 0.02;
			self.fadeInTicks--;
		}
		self.x += self.dx;
		self.y += self.dy;
		self.dx *= 0.80;
		self.dy *= 0.80;
		if (self.x < 150 || self.x > 2048 - 150 || self.y < 700 || self.y > 2732 - 150) {
			self.x = Math.max(Math.min(self.x, 2048 - 150), 150);
			self.y = Math.max(Math.min(self.y, 2732 - 150), 700);
		}
	};
	self.flashRed = function () {
		self.children[0].tint = 0xFF0000;
		self.fadeOutRedTint = 10;
	};
});
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = XS.getAsset('bullet', 'Bullet', .5, .5);
	bulletGraphics.y -= 150;
	bulletGraphics.blendMode = 1;
	self.addChild(bulletGraphics);
	self.dx = 0;
	self.dy = 0;
	self.move = function () {
		self.dx *= 1.02;
		self.dy *= 1.02;
		self.x += self.dx * 4;
		self.y += self.dy * 4;
		if (self.x < 150 || self.x > 2048 - 150 || self.y < 700 || self.y > 2732 - 150) {
			return true;
		}
		return false;
	};
});
var Background = Container.expand(function () {
	var self = Container.call(this);
	var backgroundGraphics = XS.getAsset('background', 'Background', .5, .5);
	backgroundGraphics.x = 2048 / 2;
	backgroundGraphics.y = 2732 / 2 + 300;
	self.addChild(backgroundGraphics);
	self.exitDoor = self.addChildAt(new ExitDoor(), 1);
	self.exitDoor.x = 2048 / 2;
	self.exitDoor.y = 2732 / 2 - 670 + 400;
	self.exitDoor.visible = false;
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	self.lineIntersectsObstacle = function (x1, y1, x2, y2) {
		for (var i = 0; i < obstacles.length; i++) {
			var dx = obstacles[i].x - x1;
			var dy = obstacles[i].y - y1;
			var distance = Math.sqrt(dx * dx + dy * dy);
			if (distance < obstacles[i].width / 2) {
				return true;
			}
		}
		return false;
	};
	self.allEnemiesKilled = false;
	self.setPlayerTarget = function (x, y) {
		x = Math.max(Math.min(x, 2048 - 150), 150);
		y = Math.max(Math.min(y, 2732 - 150), 700);
		player.setTarget(x, y);
		targetIndicator.x = x;
		targetIndicator.y = y;
		targetIndicator.visible = true;
	};
	self.checkEnemies = function () {
		if (!self.allEnemiesKilled && enemies.length === 0 && spawnIndicators.length === 0) {
			background.exitDoor.visible = true;
			self.allEnemiesKilled = true;
			overlay.flash(0xFFFFFF, 1000);
			self.setPlayerTarget(background.exitDoor.x, background.exitDoor.y - 300);
		}
	};
	self.rotateBackground = function () {
		background.children[1].rotate();
	};
	self.particleMove = function () {
		for (var i = particles.length - 1; i >= 0; i--) {
			if (particles[i].alpha <= 0) {
				particles[i].destroy();
				particles.splice(i, 1);
			} else {
				particles[i].move();
			}
		}
	};
	self.bulletMove = function () {
		for (var i = bullets.length - 1; i >= 0; i--) {
			if (bullets[i].move()) {
				self.createExplosion(bullets[i].x, bullets[i].y);
				bullets[i].destroy();
				bullets.splice(i, 1);
			} else {
				bullets[i].move();
				for (var j = 0; j < enemies.length; j++) {
					if (bullets[i].intersects(enemies[j])) {
						enemies[j].health -= 10;
						enemies[j].healthBar.updateHealth(enemies[j].health);
						enemies[j].flashRed();
						if (enemies[j].health <= 0) {
							enemies[j].destroy();
							enemies.splice(j, 1);
						} else {
							var angle = Math.atan2(bullets[i].dy, bullets[i].dx);
							enemies[j].x += Math.cos(angle) * 15;
							enemies[j].y += Math.sin(angle) * 15;
							enemies[j].dx = Math.cos(angle) * 10;
							enemies[j].dy = Math.sin(angle) * 10;
						}
						self.createExplosion(bullets[i].x, bullets[i].y);
						bullets[i].destroy();
						bullets.splice(i, 1);
						break;
					}
				}
			}
		}
	};
	self.enemyMove = function () {
		for (var i = 0; i < enemies.length; i++) {
			enemies[i].move();
		}
	};
	self.playerMove = function () {
		player.move(0, 0);
		var dx = player.targetX - player.x;
		var dy = player.targetY - player.y;
		var distance = Math.sqrt(dx * dx + dy * dy);
		if (distance < player.speed && XS.ticks - player.lastShot >= 60 && enemies.length > 0) {
			player.lastShot = XS.ticks;
			var bullet = player.shoot(enemies);
			bullets.push(bullet);
			self.addChild(bullet);
		}
		if (distance < player.speed) {
			targetIndicator.visible = false;
			if (self.allEnemiesKilled) {
				self.spawnNextWave();
			}
		}
	};
	var spawnIndicators = [];
	self.isTooClose = function (x, y) {
		for (var i = 0; i < spawnIndicators.length; i++) {
			var dx = spawnIndicators[i].x - x;
			var dy = spawnIndicators[i].y - y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			if (distance < 200) {
				return true;
			}
		}
		return false;
	};
	self.spawnEnemies = function (count) {
		for (var i = 0; i < count; i++) {
			var x, y;
			do {
				x = Math.random() * (2048 - 300) + 150;
				y = Math.random() * (2732 - 850) + 700;
			} while (self.isTooClose(x, y));
			var spawnIndicator = self.addChild(new EnemySpawnIndicator());
			spawnIndicator.x = x;
			spawnIndicator.y = y;
			spawnIndicators.push(spawnIndicator);
			(function (spawnIndicator) {
				XS.setTimeout(function () {
					var enemy = self.addChild(new Enemy());
					enemy.x = spawnIndicator.x;
					enemy.y = spawnIndicator.y;
					enemies.push(enemy);
					spawnIndicator.destroy();
					enemy.animateIn();
					var index = spawnIndicators.indexOf(spawnIndicator);
					if (index > -1) {
						spawnIndicators.splice(index, 1);
					}
				}, 3000);
			})(spawnIndicator);
		}
	};
	self.createExplosion = function (x, y) {
		for (var j = 0; j < 10; j++) {
			var particle = new ExplosionParticle();
			particle.x = x;
			particle.y = y;
			particle.dx = (Math.random() - 0.5) * 10;
			particle.dy = (Math.random() - 0.5) * 7;
			self.addChild(particle);
			particles.push(particle);
		}
	};
	var particles = [];
	self.sortGameObjects = function () {
		self.children.sort(function (a, b) {
			return a.y < b.y ? -1 : 1;
		});
		self.setChildIndex(targetIndicator, 1);
	};
	var background = self.addChild(new Background());
	var overlay = self.addChild(new OverlayElement());
	overlay.x = 2048 / 2;
	overlay.y = 2732;
	var targetIndicator = new TargetIndicator();
	var player = self.addChild(new Player());
	player.x = 2048 / 2;
	player.y = 2732 - player.height;
	player.setTarget(player.x, player.y);
	targetIndicator.x = player.x;
	targetIndicator.y = player.y;
	self.addChild(targetIndicator);
	var enemies = [];
	self.spawnEnemies(1);
	var obstacleSpacing = 2048 / 3;
	for (var i = 0; i < 2; i++) {
		var obstacle = new Obstacle();
		obstacle.x = obstacleSpacing * (i + 1);
		obstacle.y = 2732 / 2 + 500;
		self.addChild(obstacle);
	}
	var bullets = [];
	XS.on('tick', function () {
		self.playerMove();
		self.bulletMove();
		self.enemyMove();
		self.particleMove();
		self.rotateBackground();
		self.sortGameObjects();
		self.checkEnemies();
	});
	self.spawnNextWave = function () {
		player.x = 2048 / 2;
		player.y = 2732 - player.height;
		player.setTarget(player.x, player.y);
		background.exitDoor.visible = false;
		self.allEnemiesKilled = false;
		self.spawnEnemies(5);
		overlay.flash(0x000000, 1000);
	};
	stage.on('down', function (obj) {
		if (!self.allEnemiesKilled) {
			var pos = obj.event.getLocalPosition(self);
			self.setPlayerTarget(pos.x, pos.y);
		}
	});
});

===================================================================
--- original.js
+++ change.js
@@ -95,9 +95,9 @@
 		for (var i = 0; i < enemies.length; i++) {
 			var dx = enemies[i].x - self.x;
 			var dy = enemies[i].y - self.y;
 			var distance = Math.sqrt(dx * dx + dy * dy);
-			if (distance < nearestDistance) {
+			if (distance < nearestDistance && !self.parent.lineIntersectsObstacle(self.x, self.y, enemies[i].x, enemies[i].y)) {
 				nearestDistance = distance;
 				nearestEnemy = enemies[i];
 			}
 		}
@@ -227,8 +227,19 @@
 	self.exitDoor.visible = false;
 });
 var Game = Container.expand(function () {
 	var self = Container.call(this);
+	self.lineIntersectsObstacle = function (x1, y1, x2, y2) {
+		for (var i = 0; i < obstacles.length; i++) {
+			var dx = obstacles[i].x - x1;
+			var dy = obstacles[i].y - y1;
+			var distance = Math.sqrt(dx * dx + dy * dy);
+			if (distance < obstacles[i].width / 2) {
+				return true;
+			}
+		}
+		return false;
+	};
 	self.allEnemiesKilled = false;
 	self.setPlayerTarget = function (x, y) {
 		x = Math.max(Math.min(x, 2048 - 150), 150);
 		y = Math.max(Math.min(y, 2732 - 150), 700);