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

/**** 
* Classes
****/ 
// Bird class
var Bird = Container.expand(function () {
	var self = Container.call(this);
	var birdSprite = self.attachAsset('bird', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.vy = 0; // vertical speed
	self.gravity = 0.7; // gravity per frame (further reduced for slower fall)
	self.flapStrength = -18; // negative = up (further reduced for softer flap)
	self.flap = function () {
		self.vy = self.flapStrength;
		LK.getSound('flap').play();
		// Animate a quick scale for feedback
		tween(birdSprite, {
			scaleY: 0.7
		}, {
			duration: 60,
			easing: tween.cubicOut,
			onFinish: function onFinish() {
				tween(birdSprite, {
					scaleY: 1
				}, {
					duration: 120,
					easing: tween.cubicOut
				});
			}
		});
	};
	self.update = function () {
		self.vy += self.gravity;
		self.y += self.vy;
		// Clamp rotation for visual feedback
		var maxAngle = Math.PI / 4;
		var minAngle = -Math.PI / 6;
		var t = Math.max(-1, Math.min(1, self.vy / 40));
		birdSprite.rotation = minAngle + (maxAngle - minAngle) * (t + 1) / 2;
	};
	return self;
});
// Ground class
var Ground = Container.expand(function () {
	var self = Container.call(this);
	var groundSprite = self.attachAsset('ground', {
		anchorX: 0,
		anchorY: 0
	});
	return self;
});
// PipePair class (top and bottom pipes)
var PipePair = Container.expand(function () {
	var self = Container.call(this);
	// Pipe gap size
	self.gap = 600;
	// Pipe speed
	self.speed = 9;
	// Top pipe
	self.topPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 1
	});
	// Bottom pipe
	self.bottomPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 0
	});
	// Set pipes' positions based on gapY
	self.setGapY = function (gapY) {
		self.topPipe.y = gapY - self.gap / 2;
		self.bottomPipe.y = gapY + self.gap / 2;
		// Flip top pipe upside down
		self.topPipe.rotation = Math.PI;
		// Extend top pipe to reach ceiling
		self.topPipe.height = self.topPipe.y + 750;
		// Extend bottom pipe to reach ground
		self.bottomPipe.height = GROUND_Y - self.bottomPipe.y + 750;
	};
	// For scoring
	self.passed = false;
	self.update = function () {
		self.x -= self.speed;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x87ceeb // Sky blue
});

/**** 
* Game Code
****/ 
// Sound: Hit
// Sound: Score
// Sound: Flap
// Ground: brown box
// Pipe: green box
// Bird: yellow ellipse
// Game constants
var BIRD_START_X = 600;
var BIRD_START_Y = 1100;
var PIPE_INTERVAL = 90; // frames between pipes
var PIPE_MIN_Y = 500;
var PIPE_MAX_Y = 2000;
var GROUND_Y = 2732 - 120;
// Game state
var bird;
var pipes = [];
var ground;
var score = 0;
var scoreTxt;
var gameStarted = false;
var gameOver = false;
var lastPipeTick = 0;
// GUI score
scoreTxt = new Text2('0', {
	size: 150,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
// Add ground
ground = new Ground();
ground.x = 0;
ground.y = GROUND_Y;
game.addChild(ground);
// Add bird
bird = new Bird();
bird.x = BIRD_START_X;
bird.y = BIRD_START_Y;
game.addChild(bird);
// Reset function
function resetGame() {
	// Remove pipes
	for (var i = 0; i < pipes.length; i++) {
		pipes[i].destroy();
	}
	pipes = [];
	// Reset bird
	bird.x = BIRD_START_X;
	bird.y = BIRD_START_Y;
	bird.vy = 0;
	// Reset score
	score = 0;
	scoreTxt.setText(score);
	// Reset state
	gameStarted = false;
	gameOver = false;
	lastPipeTick = LK.ticks;
}
// Start game on first tap
game.down = function (x, y, obj) {
	if (gameOver) return;
	if (!gameStarted) {
		gameStarted = true;
		bird.flap();
		return;
	}
	bird.flap();
};
// Main update loop
game.update = function () {
	if (gameOver) return;
	if (!gameStarted) {
		// Bird idle bounce
		bird.y = BIRD_START_Y + Math.sin(LK.ticks / 20) * 20;
		return;
	}
	bird.update();
	// Add pipes
	if (LK.ticks - lastPipeTick > PIPE_INTERVAL) {
		lastPipeTick = LK.ticks;
		var gapY = PIPE_MIN_Y + Math.floor(Math.random() * (PIPE_MAX_Y - PIPE_MIN_Y));
		var pipePair = new PipePair();
		pipePair.x = 2048 + 200;
		pipePair.setGapY(gapY);
		pipes.push(pipePair);
		game.addChild(pipePair);
	}
	// Update pipes and check for collisions
	for (var i = pipes.length - 1; i >= 0; i--) {
		var pipe = pipes[i];
		pipe.update();
		// Collision with pipes
		if (bird.x + 60 > pipe.x - 60 && bird.x - 60 < pipe.x + 60 // horizontal overlap
		) {
			// Top pipe
			if (bird.y - 45 < pipe.topPipe.y) {
				// Hit top pipe
				endGame();
				return;
			}
			// Bottom pipe
			if (bird.y + 45 > pipe.bottomPipe.y) {
				// Hit bottom pipe
				endGame();
				return;
			}
		}
		// Score: passed pipe
		if (!pipe.passed && pipe.x + 60 < bird.x - 60) {
			pipe.passed = true;
			score += 1;
			scoreTxt.setText(score);
			LK.getSound('score').play();
		}
		// Remove off-screen pipes
		if (pipe.x < -300) {
			pipe.destroy();
			pipes.splice(i, 1);
		}
	}
	// Collision with ground
	if (bird.y + 45 > GROUND_Y) {
		endGame();
		return;
	}
	// Collision with ceiling
	if (bird.y - 45 < 0) {
		bird.y = 45;
		bird.vy = 0;
	}
};
// End game
function endGame() {
	if (gameOver) return;
	gameOver = true;
	LK.getSound('hit').play();
	LK.effects.flashScreen(0xff0000, 600);
	// Show game over popup (handled by LK)
	LK.showGameOver();
}
// Reset on game over (handled by LK)
game.on('reset', function () {
	resetGame();
});
// Initial reset
resetGame();

===================================================================
--- original.js
+++ change.js
@@ -75,8 +75,10 @@
 	// Set pipes' positions based on gapY
 	self.setGapY = function (gapY) {
 		self.topPipe.y = gapY - self.gap / 2;
 		self.bottomPipe.y = gapY + self.gap / 2;
+		// Flip top pipe upside down
+		self.topPipe.rotation = Math.PI;
 		// Extend top pipe to reach ceiling
 		self.topPipe.height = self.topPipe.y + 750;
 		// Extend bottom pipe to reach ground
 		self.bottomPipe.height = GROUND_Y - self.bottomPipe.y + 750;