===================================================================
--- original.js
+++ change.js
@@ -1,6 +1,532 @@
-/****
+/**** 
+* Plugins
+****/ 
+var tween = LK.import("@upit/tween.v1");
+
+/**** 
+* Classes
+****/ 
+// Bullet
+var Bullet = Container.expand(function () {
+	var self = Container.call(this);
+	var bullet = self.attachAsset('bullet', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = bullet.width;
+	self.height = bullet.height;
+	self.speed = -36; // Upwards
+	self.update = function () {
+		self.y += self.speed;
+	};
+	return self;
+});
+// Enemy base class
+var Enemy = Container.expand(function () {
+	var self = Container.call(this);
+	self.type = 'enemy';
+	self.hp = 1;
+	self.speed = 8;
+	self.scoreValue = 1;
+	self.update = function () {};
+	return self;
+});
+// Skeleton enemy
+var Skeleton = Enemy.expand(function () {
+	var self = Enemy.call(this);
+	var skeleton = self.attachAsset('enemy_skeleton', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = skeleton.width;
+	self.height = skeleton.height;
+	self.hp = 1;
+	self.speed = 12 + Math.random() * 4;
+	self.scoreValue = 2;
+	self.update = function () {
+		self.y += self.speed;
+	};
+	return self;
+});
+// Goblin enemy
+var Goblin = Enemy.expand(function () {
+	var self = Enemy.call(this);
+	var goblin = self.attachAsset('enemy_goblin', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = goblin.width;
+	self.height = goblin.height;
+	self.hp = 2;
+	self.speed = 10 + Math.random() * 4;
+	self.scoreValue = 3;
+	self.update = function () {
+		self.y += self.speed;
+	};
+	return self;
+});
+// Bat enemy
+var Bat = Enemy.expand(function () {
+	var self = Enemy.call(this);
+	var bat = self.attachAsset('enemy_bat', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = bat.width;
+	self.height = bat.height;
+	self.hp = 1;
+	self.speed = 18 + Math.random() * 6;
+	self.scoreValue = 2;
+	self.update = function () {
+		self.y += self.speed;
+		self.x += Math.sin(LK.ticks / 12 + self._batWobble) * 8;
+	};
+	self._batWobble = Math.random() * Math.PI * 2;
+	return self;
+});
+// Player Minecart
+var Minecart = Container.expand(function () {
+	var self = Container.call(this);
+	var cart = self.attachAsset('minecart', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = cart.width;
+	self.height = cart.height;
+	self.weapon = 'gun'; // 'gun' or 'knife'
+	self.weaponLevel = 1; // Upgrades increase this
+	self.invincible = false;
+	self.invincibleTimer = 0;
+	self.attackCooldown = 0;
+	self.knifeSwinging = false;
+	self.knife = null;
+	// Flash minecart when hit
+	self.flash = function () {
+		self.invincible = true;
+		self.invincibleTimer = 60; // 1 second at 60fps
+		tween(self, {
+			alpha: 0.5
+		}, {
+			duration: 100,
+			easing: tween.easeOut,
+			onFinish: function onFinish() {
+				tween(self, {
+					alpha: 1
+				}, {
+					duration: 100
+				});
+			}
+		});
+	};
+	// Switch weapon
+	self.setWeapon = function (type) {
+		self.weapon = type;
+	};
+	// Upgrade weapon
+	self.upgradeWeapon = function () {
+		self.weaponLevel += 1;
+		if (self.weaponLevel > 3) self.weaponLevel = 3;
+	};
+	// Knife attack animation
+	self.swingKnife = function () {
+		if (self.knifeSwinging) return;
+		self.knifeSwinging = true;
+		if (!self.knife) {
+			self.knife = self.attachAsset('knife', {
+				anchorX: 0.1,
+				anchorY: 0.5,
+				x: self.width / 2 + 20,
+				y: 0,
+				rotation: 0
+			});
+		}
+		self.knife.visible = true;
+		self.knife.rotation = -0.7;
+		tween(self.knife, {
+			rotation: 0.7
+		}, {
+			duration: 180,
+			easing: tween.cubicOut,
+			onFinish: function onFinish() {
+				self.knife.visible = false;
+				self.knifeSwinging = false;
+				self.knife.rotation = -0.7;
+			}
+		});
+	};
+	return self;
+});
+// Obstacle (rock)
+var Obstacle = Container.expand(function () {
+	var self = Container.call(this);
+	var rock = self.attachAsset('obstacle_rock', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = rock.width;
+	self.height = rock.height;
+	self.speed = 14 + Math.random() * 6;
+	self.update = function () {
+		self.y += self.speed;
+	};
+	return self;
+});
+// Upgrade (gun or knife)
+var Upgrade = Container.expand(function () {
+	var self = Container.call(this);
+	self.kind = Math.random() < 0.5 ? 'gun' : 'knife';
+	var assetId = self.kind === 'gun' ? 'upgrade_gun' : 'upgrade_knife';
+	var upg = self.attachAsset(assetId, {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.width = upg.width;
+	self.height = upg.height;
+	self.speed = 10 + Math.random() * 4;
+	self.update = function () {
+		self.y += self.speed;
+	};
+	return self;
+});
+
+/**** 
 * Initialize Game
-****/
+****/ 
 var game = new LK.Game({
-	backgroundColor: 0x000000
-});
\ No newline at end of file
+	backgroundColor: 0x181818
+});
+
+/**** 
+* Game Code
+****/ 
+// Upgrade: Knife
+// Upgrade: Gun
+// Obstacle: Rock
+// Enemy: Skeleton
+// Enemy: Goblin
+// Enemy: Bat
+// Player's bullet
+// Player's knife
+// Minecart (player)
+// Game constants
+var GAME_W = 2048;
+var GAME_H = 2732;
+var TRACK_LEFT = 300;
+var TRACK_RIGHT = GAME_W - 300;
+var PLAYER_Y = GAME_H - 350;
+// Game state
+var minecart = null;
+var bullets = [];
+var enemies = [];
+var obstacles = [];
+var upgrades = [];
+var dragNode = null;
+var lastTouchX = 0;
+var lastTouchY = 0;
+var scoreTxt = null;
+var lastScore = 0;
+var gameOver = false;
+var spawnTimer = 0;
+var obstacleTimer = 0;
+var upgradeTimer = 0;
+var difficulty = 1;
+var knifeHitEnemies = [];
+var lastKnifeSwingTick = -100;
+// Score display
+scoreTxt = new Text2('0', {
+	size: 120,
+	fill: "#fff"
+});
+scoreTxt.anchor.set(0.5, 0);
+LK.gui.top.addChild(scoreTxt);
+// Create player
+minecart = new Minecart();
+game.addChild(minecart);
+minecart.x = GAME_W / 2;
+minecart.y = PLAYER_Y;
+// Touch controls: drag minecart horizontally
+game.down = function (x, y, obj) {
+	if (gameOver) return;
+	dragNode = minecart;
+	lastTouchX = x;
+	lastTouchY = y;
+};
+game.up = function (x, y, obj) {
+	dragNode = null;
+};
+game.move = function (x, y, obj) {
+	if (gameOver) return;
+	if (dragNode === minecart) {
+		// Only allow horizontal movement within track
+		var nx = x;
+		if (nx < TRACK_LEFT) nx = TRACK_LEFT;
+		if (nx > TRACK_RIGHT) nx = TRACK_RIGHT;
+		minecart.x = nx;
+	}
+};
+// Tap to attack (shoot or knife)
+game.tap = function (x, y, obj) {
+	if (gameOver) return;
+	if (minecart.weapon === 'gun') {
+		if (minecart.attackCooldown <= 0) {
+			fireBullet();
+			minecart.attackCooldown = 12 - minecart.weaponLevel * 2; // Faster with upgrades
+			if (minecart.attackCooldown < 4) minecart.attackCooldown = 4;
+		}
+	} else if (minecart.weapon === 'knife') {
+		if (LK.ticks - lastKnifeSwingTick > 18) {
+			minecart.swingKnife();
+			lastKnifeSwingTick = LK.ticks;
+		}
+	}
+};
+// Fire bullet(s)
+function fireBullet() {
+	var spread = minecart.weaponLevel;
+	for (var i = 0; i < spread; ++i) {
+		var b = new Bullet();
+		b.x = minecart.x + (i - (spread - 1) / 2) * 40;
+		b.y = minecart.y - minecart.height / 2 - 10;
+		bullets.push(b);
+		game.addChild(b);
+	}
+}
+// Main update loop
+game.update = function () {
+	if (gameOver) return;
+	// Difficulty scaling
+	if (LK.ticks % 300 === 0 && difficulty < 10) {
+		difficulty += 1;
+	}
+	// Attack cooldown
+	if (minecart.attackCooldown > 0) minecart.attackCooldown -= 1;
+	// Invincibility timer
+	if (minecart.invincible) {
+		minecart.invincibleTimer -= 1;
+		if (minecart.invincibleTimer <= 0) {
+			minecart.invincible = false;
+		}
+	}
+	// Bullets update
+	for (var i = bullets.length - 1; i >= 0; --i) {
+		var b = bullets[i];
+		b.update();
+		if (b.y < -50) {
+			b.destroy();
+			bullets.splice(i, 1);
+			continue;
+		}
+		// Bullet hits enemy
+		for (var j = enemies.length - 1; j >= 0; --j) {
+			var e = enemies[j];
+			if (b.intersects(e)) {
+				e.hp -= 1;
+				b.destroy();
+				bullets.splice(i, 1);
+				if (e.hp <= 0) {
+					addScore(e.scoreValue);
+					e.destroy();
+					enemies.splice(j, 1);
+				}
+				break;
+			}
+		}
+	}
+	// Enemies update
+	for (var i = enemies.length - 1; i >= 0; --i) {
+		var e = enemies[i];
+		e.update();
+		if (e.y > GAME_H + 100) {
+			e.destroy();
+			enemies.splice(i, 1);
+			continue;
+		}
+		// Enemy hits minecart
+		if (!minecart.invincible && e.intersects(minecart)) {
+			minecart.flash();
+			LK.effects.flashScreen(0xff0000, 600);
+			// End game
+			LK.showGameOver();
+			gameOver = true;
+			return;
+		}
+		// Enemy hit by knife
+		if (minecart.weapon === 'knife' && minecart.knife && minecart.knife.visible && !knifeHitEnemies.includes(e)) {
+			// Knife is in swing, check collision
+			var knifeGlobal = minecart.toGlobal(minecart.knife.position);
+			var knifeRect = new Rectangle(knifeGlobal.x - 30, knifeGlobal.y - 12, 60, 24);
+			var enemyRect = new Rectangle(e.x - e.width / 2, e.y - e.height / 2, e.width, e.height);
+			if (rectsIntersect(knifeRect, enemyRect)) {
+				e.hp -= 1;
+				knifeHitEnemies.push(e);
+				if (e.hp <= 0) {
+					addScore(e.scoreValue);
+					e.destroy();
+					enemies.splice(i, 1);
+				}
+			}
+		}
+	}
+	// Reset knife hit list if knife not swinging
+	if (!(minecart.knife && minecart.knife.visible)) {
+		knifeHitEnemies = [];
+	}
+	// Obstacles update
+	for (var i = obstacles.length - 1; i >= 0; --i) {
+		var o = obstacles[i];
+		o.update();
+		if (o.y > GAME_H + 100) {
+			o.destroy();
+			obstacles.splice(i, 1);
+			continue;
+		}
+		// Obstacle hits minecart
+		if (!minecart.invincible && o.intersects(minecart)) {
+			minecart.flash();
+			LK.effects.flashScreen(0xff0000, 600);
+			LK.showGameOver();
+			gameOver = true;
+			return;
+		}
+	}
+	// Upgrades update
+	for (var i = upgrades.length - 1; i >= 0; --i) {
+		var u = upgrades[i];
+		u.update();
+		if (u.y > GAME_H + 100) {
+			u.destroy();
+			upgrades.splice(i, 1);
+			continue;
+		}
+		// Pickup
+		if (u.intersects(minecart)) {
+			if (u.kind === 'gun') {
+				minecart.setWeapon('gun');
+				minecart.upgradeWeapon();
+			} else {
+				minecart.setWeapon('knife');
+				minecart.upgradeWeapon();
+			}
+			u.destroy();
+			upgrades.splice(i, 1);
+		}
+	}
+	// Spawning enemies
+	spawnTimer -= 1;
+	if (spawnTimer <= 0) {
+		spawnEnemy();
+		spawnTimer = Math.max(24, 60 - difficulty * 4 - Math.floor(Math.random() * 10));
+	}
+	// Spawning obstacles
+	obstacleTimer -= 1;
+	if (obstacleTimer <= 0) {
+		if (Math.random() < 0.5 + difficulty * 0.04) {
+			spawnObstacle();
+		}
+		obstacleTimer = 90 + Math.floor(Math.random() * 60) - difficulty * 4;
+		if (obstacleTimer < 30) obstacleTimer = 30;
+	}
+	// Spawning upgrades
+	upgradeTimer -= 1;
+	if (upgradeTimer <= 0) {
+		if (Math.random() < 0.18) {
+			spawnUpgrade();
+		}
+		upgradeTimer = 600 + Math.floor(Math.random() * 300);
+	}
+	// Update score display
+	if (LK.getScore() !== lastScore) {
+		scoreTxt.setText(LK.getScore());
+		lastScore = LK.getScore();
+	}
+};
+// Spawn enemy
+function spawnEnemy() {
+	var enemyType = Math.random();
+	var e = null;
+	var x = TRACK_LEFT + 80 + Math.random() * (TRACK_RIGHT - TRACK_LEFT - 160);
+	if (enemyType < 0.33) {
+		e = new Bat();
+	} else if (enemyType < 0.66) {
+		e = new Goblin();
+	} else {
+		e = new Skeleton();
+	}
+	e.x = x;
+	e.y = -80;
+	enemies.push(e);
+	game.addChild(e);
+}
+// Spawn obstacle
+function spawnObstacle() {
+	var o = new Obstacle();
+	o.x = TRACK_LEFT + 80 + Math.random() * (TRACK_RIGHT - TRACK_LEFT - 160);
+	o.y = -60;
+	obstacles.push(o);
+	game.addChild(o);
+}
+// Spawn upgrade
+function spawnUpgrade() {
+	var u = new Upgrade();
+	u.x = TRACK_LEFT + 80 + Math.random() * (TRACK_RIGHT - TRACK_LEFT - 160);
+	u.y = -60;
+	upgrades.push(u);
+	game.addChild(u);
+}
+// Add score
+function addScore(val) {
+	LK.setScore(LK.getScore() + val);
+}
+// Rectangle intersection helper
+function rectsIntersect(r1, r2) {
+	return !(r2.x > r1.x + r1.width || r2.x + r2.width < r1.x || r2.y > r1.y + r1.height || r2.y + r2.height < r1.y);
+}
+// Touch to attack (simulate tap on mobile)
+game.down = function (origDown) {
+	return function (x, y, obj) {
+		if (origDown) origDown(x, y, obj);
+		game.tap(x, y, obj);
+	};
+}(game.down);
+// Reset game state on game over
+LK.on('gameover', function () {
+	gameOver = true;
+});
+// Reset game state on new game
+LK.on('newgame', function () {
+	gameOver = false;
+	LK.setScore(0);
+	scoreTxt.setText('0');
+	// Remove all objects
+	for (var i = 0; i < bullets.length; ++i) bullets[i].destroy();
+	for (var i = 0; i < enemies.length; ++i) enemies[i].destroy();
+	for (var i = 0; i < obstacles.length; ++i) obstacles[i].destroy();
+	for (var i = 0; i < upgrades.length; ++i) upgrades[i].destroy();
+	bullets = [];
+	enemies = [];
+	obstacles = [];
+	upgrades = [];
+	minecart.x = GAME_W / 2;
+	minecart.y = PLAYER_Y;
+	minecart.weapon = 'gun';
+	minecart.weaponLevel = 1;
+	minecart.invincible = false;
+	minecart.invincibleTimer = 0;
+	minecart.attackCooldown = 0;
+	minecart.knifeSwinging = false;
+	minecart.setWeapon('gun');
+	difficulty = 1;
+	spawnTimer = 0;
+	obstacleTimer = 0;
+	upgradeTimer = 0;
+	knifeHitEnemies = [];
+	lastKnifeSwingTick = -100;
+});
+// Initial state
+spawnTimer = 0;
+obstacleTimer = 60;
+upgradeTimer = 600;
+difficulty = 1;
+gameOver = false;
+LK.setScore(0);
+scoreTxt.setText('0');
\ No newline at end of file