var Pickup = Container.expand(function (parent, x, y) {
	var self = Container.call(this);
	parent.addChild(self);
	self.x = x;
	self.y = y;
	self.update = update;
	var activeDist = 300;
	var activeDistSqr = activeDist * activeDist;
	var collectDist = 50;
	var collectDistSqr = collectDist * collectDist;
	var collectSpeed = 25;
	var collectOffset = -50;
	var active = false;
	var variant = Math.floor(Math.random() * 3);
	var graphics = self.createAsset('pickup' + variant, 'Pickup graphics', 0.5, 0.5);
	function update(player, velocityX, velocityY) {
		var dx = player.x - self.x;
		var dy = player.y + collectOffset - self.y;
		var distSqr = dx * dx + dy * dy;
		if (self.active) {
			var dist = Math.sqrt(distSqr);
			self.x += dx / dist * collectSpeed;
			self.y += dy / dist * collectSpeed;
		} else if (distSqr <= activeDistSqr) {
			self.active = true;
		} else {
			self.x -= velocityX;
			self.y -= velocityY;
		}
		return distSqr <= collectDistSqr;
	}
});
var LandscapeTile = Container.expand(function (parent, x, y, args) {
	var self = Container.call(this);
	parent.addChild(self);
	self.x = x;
	self.y = y;
	var landscapeTiles = args.landscapeTiles;
	var lookup = args.lookup;
	var xIndex = args.xIndex;
	var yIndex = args.yIndex;
	var width = args.width;
	var height = args.height;
	var density = args.density;
	var pickups = args.pickups;
	var key = args.key;
	self.checkCollision = checkCollision;
	self.activate = activate;
	self.width = width;
	self.height = height;
	self.active = false;
	self.key = key;
	var obstructions = [];
	var visual = self.createAsset('hitbox', 'Landscape area', 0.5, 0.5);
	visual.alpha = 0;
	visual.width = width;
	visual.height = height;
	function checkCollision(player) {
		var reach = 100;
		var dx = Math.abs(player.x - self.x);
		var dy = Math.abs(player.y - self.y);
		if (dx < width / 2 + reach && dy < height / 2 + reach) {
			for (var i = 0; i < obstructions.length; i++) {
				var obstruction = obstructions[i];
				if (obstruction.active && player.hitbox.intersects(obstruction.hitbox)) {
					obstruction.deactivate();
					return true;
				}
			}
		}
		return false;
	}
	function activate() {
		if (!self.active) {
			self.active = true;
			var densityChance = Math.pow(1 + density, 3) / 100;
			var obstructionTypes = ['largeTree', 'smallTree', 'deadTree', 'rock', 'stump'];
			var clearanceDist = 150;
			var clearanceDistSqr = clearanceDist * clearanceDist;
			var spawnBorder = 25;
			var cellSize = 150;
			var cols = Math.ceil(width / cellSize);
			var rows = Math.ceil(height / cellSize);
			var cellWidth = width / cols;
			var cellHeight = height / rows;
			var cellInnerWidth = Math.max(0, cellWidth - 2 * spawnBorder);
			var cellInnerHeight = Math.max(0, cellHeight - 2 * spawnBorder);
			var pickup;
			if (Math.random() <= 0.1) {
				var pickupX = self.x - width / 2 + spawnBorder + Math.random() * (width - spawnBorder * 2);
				var pickupY = self.y - height / 2 + spawnBorder + Math.random() * (height - spawnBorder * 2);
				pickups.push(pickup = new Pickup(parent, pickupX, pickupY));
			}
			for (i = 0; i < cols; i++) {
				for (j = 0; j < rows; j++) {
					if (Math.random() <= densityChance) {
						var canPlace = true;
						var obsX = cellWidth * i + spawnBorder + Math.random() * cellInnerWidth - width / 2;
						var obsY = cellHeight * j + spawnBorder + Math.random() * cellInnerHeight - height / 2;
						if (pickup) {
							var dx = pickup.x - obsX;
							var dy = pickup.y - obsY;
							var distSqr = dx * dx + dy * dy;
							if (distSqr <= clearanceDistSqr) {
								canPlace = false;
							}
						}
						if (canPlace) {
							var type = obstructionTypes[Math.floor(Math.random() * obstructionTypes.length)];
							obstructions.push(new Obstruction(self, obsX, obsY, type));
						}
					}
				}
			}
		}
		var leftKey = xIndex - 1 + ':' + yIndex;
		var rightKey = xIndex + 1 + ':' + yIndex;
		var downKey = xIndex + ':' + (yIndex + 1);
		if (!lookup[leftKey]) {
			landscapeTiles.push(lookup[leftKey] = new LandscapeTile(parent, self.x - width, self.y, {
				key: leftKey,
				density: Math.random(),
				xIndex: xIndex - 1,
				yIndex,
				landscapeTiles,
				width,
				height,
				lookup,
				pickups
			}));
		}
		if (!lookup[rightKey]) {
			landscapeTiles.push(lookup[rightKey] = new LandscapeTile(parent, self.x + width, self.y, {
				key: rightKey,
				density: Math.random(),
				xIndex: xIndex + 1,
				yIndex,
				landscapeTiles,
				width,
				height,
				lookup,
				pickups
			}));
		}
		if (!lookup[downKey]) {
			landscapeTiles.push(lookup[downKey] = new LandscapeTile(parent, self.x, self.y + height, {
				key: downKey,
				density: Math.random(),
				yIndex: yIndex + 1,
				xIndex,
				landscapeTiles,
				width,
				height,
				lookup,
				pickups
			}));
		}
	}
});
var Obstruction = Container.expand(function (parent, x, y, type) {
	var self = Container.call(this);
	parent.addChild(self);
	self.x = x;
	self.y = y;
	self.active = true;
	var graphics = self.createAsset(type, 'Obstruction graphics', 0.5, 1);
	var hitbox = self.createAsset('hitbox', 'Obstruction hitbox', 0.5, 0.5);
	var randomScale = 0.9 + Math.random() * 0.2;
	hitbox.y = -25;
	hitbox.alpha = 0;
	hitbox.width = graphics.width * 0.8;
	hitbox.height = graphics.width * 0.45;
	self.scale.set(randomScale, randomScale);
	self.hitbox = hitbox;
	self.deactivate = deactivate;
	function deactivate() {
		self.active = false;
		graphics.alpha = 0.5;
	}
});
var Player = Container.expand(function (parent, x, y) {
	var self = Container.call(this);
	parent.addChild(self);
	self.x = x;
	self.y = y;
	self.update = update;
	var speed = 0;
	self.invulnerable = false;
	self.invulnerableTime = 3 * 60;
	self.invulnerableTimer = 0;
	var invulnerableReduction = 0.75;
	var platformGraphics = self.createAsset('platform', 'Platform image', 0.5, 0.5);
	var playerGraphics = self.createAsset('player', 'Player character', 0.575, 1);
	var hitbox = self.createAsset('hitbox', 'Player Hitbox', 0.5, 0.5);
	hitbox.width = 25;
	hitbox.height = 25;
	hitbox.alpha = 0;
	self.hitbox = hitbox;
	function update(targetPosition) {
		if (self.invulnerable) {
			self.invulnerableTimer--;
			if (self.invulnerableTimer <= 0) {
				self.invulnerable = false;
			}
			self.alpha = self.invulnerableTimer % 60 < 30 ? 1 : 0.5;
		}
		var dx = targetPosition.x - self.x;
		var dy = targetPosition.y - self.y;
		var angle = angleClamp(Math.atan2(dy, dx));
		var acceleration = (Math.sin(angle) - 0.1) * 2.0;
		speed = Math.max(0, speed * 0.95 + acceleration);
		var reduction = self.invulnerable ? 1 - self.invulnerableTimer / self.invulnerableTime : 1;
		var velocityX = Math.cos(angle) * speed * reduction;
		var velocityY = Math.sin(angle) * speed * reduction;
		platformGraphics.rotation = angle + Math.PI / 2;
		playerGraphics.scale.x = velocityX < 0 ? -1 : 1;
		return {
			velocityX,
			velocityY
		};
	}
	function angleClamp(angle) {
		return angle >= 0 ? angle : angle < -Math.PI / 2 ? Math.PI : 0;
	}
});
var Trail = Container.expand(function (parent, x, y) {
	var self = Container.call(this);
	parent.addChild(self);
	self.x = x;
	self.y = y;
	var trailWidth = 20;
	var trailLength = 30;
	var trailAlpha = 0.6;
	var trailElements = [];
	self.update = update;
	function update(velocityX, velocityY) {
		var trailElement = null;
		if (velocityX !== 0 || velocityY !== 0) {
			trailElement = self.createAsset('blank', 'Trail element', 1, 0.5);
			var angle = Math.atan2(velocityY, velocityX) + Math.PI / 2;
			var speed = Math.sqrt(velocityX * velocityX + velocityY * velocityY);
			trailElement.rotation = angle;
			trailElement.scale.y = speed / 100;
		}
		trailElements.push(trailElement);
		if (trailElements.length > trailLength) {
			var removedElement = trailElements.shift();
			if (removedElement) {
				removedElement.destroy();
			}
		}
		for (var i = trailElements.length - 1; i >= 0; i--) {
			var element = trailElements[i];
			if (element) {
				var alpha = trailAlpha * (i / trailLength);
				element.x -= velocityX;
				element.y -= velocityY;
				element.alpha = alpha;
			}
		}
	}
});
var Interface = Container.expand(function (parent, x, y) {
	var self = Container.call(this);
	parent.addChild(self);
	self.x = x;
	self.y = y;
	var score = 0;
	var lives = 3;
	var lifeIcons = [];
	var scoreIcon = self.createAsset('scoreIcon', 'Score icon', 0.5, 0);
	var scoreText = new Text2('| ' + score, {
		size: 70,
		fill: "#000000",
		align: 'left'
	});
	self.addChild(scoreText);
	for (var i = 0; i < lives; i++) {
		var lifeIcon = self.createAsset('lifeIcon', 'Life icon', 1, 0);
		lifeIcon.x = -10 - i * 60;
		lifeIcon.y = scoreIcon.height + 20;
		lifeIcons.push(lifeIcon);
	}
	scoreText.x = -5;
	scoreText.y = scoreIcon.height;
	scoreText.anchor.set(0, 0);
	self.changeScore = changeScore;
	self.changeLives = changeLives;
	function changeLives(amount) {
		lives += amount;
		for (var i = 0; i < lifeIcons.length; i++) {
			lifeIcons[i].alpha = i < lives ? 1 : 0.5;
		}
		if (amount < 0) {
			LK.effects.flashScreen(0xaa0000, 300);
			if (lives <= 0) {
				LK.showGameOver();
			}
		}
	}
	function changeScore(amount) {
		score += amount;
		scoreText.setText('| ' + score);
	}
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var stageWidth = 2048;
	var stageHeight = 2732;
	var tileSize = 512;
	var playerPosX = stageWidth / 2;
	var playerPosY = stageWidth / 5;
	var tileMargin = tileSize / 2 + 100;
	var background = self.createAsset('background', 'Fullscreen background', 0, 0);
	var landscapeLookup = {};
	var landscapeTiles = [];
	var pickups = [];
	var speed = 0;
	background.width = stageWidth;
	background.height = stageHeight;
	var interface = new Interface(self, 0, 20);
	LK.gui.topCenter.addChild(interface);
	var trail = new Trail(self, playerPosX, playerPosY);
	var player = new Player(self, playerPosX, playerPosY);
	landscapeTiles.push(landscapeLookup['0:0'] = new LandscapeTile(self, player.x, player.y, {
		width: tileSize,
		height: tileSize,
		density: -1,
		lookup: landscapeLookup,
		xIndex: 0,
		yIndex: 0,
		key: '0:0',
		landscapeTiles,
		pickups
	}));
	var isMouseDown = false;
	var targetPosition = {
		x: player.x,
		y: player.y
	};
	stage.on('down', function (obj) {
		isMouseDown = true;
		updatePosition(obj.event);
	});
	stage.on('up', function (obj) {
		isMouseDown = false;
	});
	stage.on('move', function (obj) {
		if (isMouseDown) {
			updatePosition(obj.event);
		}
	});
	LK.on('tick', function () {
		var {velocityX, velocityY} = player.update(targetPosition);
		trail.update(velocityX, velocityY);
		for (var i = landscapeTiles.length - 1; i >= 0; i--) {
			var landscapeTile = landscapeTiles[i];
			landscapeTile.x -= velocityX;
			landscapeTile.y -= velocityY;
			if (landscapeTile.y < -(tileSize / 2 + tileMargin)) {
				landscapeTile.destroy();
				landscapeTiles.splice(i, 1);
				landscapeLookup[landscapeTile.key] = undefined;
			} else if (!landscapeTile.active && landscapeTile.x > -tileMargin && landscapeTile.x < stageWidth + tileMargin && landscapeTile.y < stageHeight + tileMargin) {
				landscapeTile.activate();
			} else if (landscapeTile.checkCollision(player) && !player.invulnerable) {
				player.invulnerable = true;
				player.invulnerableTimer = player.invulnerableTime;
				interface.changeLives(-1);
			}
		}
		for (var i = pickups.length - 1; i >= 0; i--) {
			var pickup = pickups[i];
			if (pickup.update(player, velocityX, velocityY)) {
				interface.changeScore(1);
				pickup.destroy();
				pickups.splice(i, 1);
			} else if (pickup.y < -(tileSize / 2 + tileMargin) || pickup.active && player.hitbox.intersects(pickup.hitbox)) {
				pickup.destroy();
				pickups.splice(i, 1);
			}
		}
	});
	function updatePosition(event) {
		var pos = event.getLocalPosition(self);
		targetPosition.x = pos.x;
		targetPosition.y = pos.y;
	}
});

===================================================================
--- original.js
+++ change.js
@@ -239,10 +239,9 @@
 			trailElement = self.createAsset('blank', 'Trail element', 1, 0.5);
 			var angle = Math.atan2(velocityY, velocityX) + Math.PI / 2;
 			var speed = Math.sqrt(velocityX * velocityX + velocityY * velocityY);
 			trailElement.rotation = angle;
-			trailElement.scale.x = speed / 100;
-			trailElement.scale.y = trailWidth / 100;
+			trailElement.scale.y = speed / 100;
 		}
 		trailElements.push(trailElement);
 		if (trailElements.length > trailLength) {
 			var removedElement = trailElements.shift();