var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.createAsset('player', 'Player character', .5, .5);
	self.gravity = 1;
	self.jumpForce = 20;
	self.velocityX = 0;
	self.velocityY = 0;
	self.setJumpForce = function (x, y) {
		this.jumpForceX = x / 12.5;
		this.jumpForceY = y / 12.5;
	};
	self.jumping = false;
	self.update = function () {
		this.x += this.velocityX;
		this.y += this.velocityY;
		this.velocityY += this.gravity;
		if (this.jumping) {
			this.velocityX *= 0.98;
			this.velocityY *= 0.98;
		} else {
			this.velocityX *= 0.98 * 5;
			this.velocityY *= 0.98 * 5;
		}
		if (this.y > 2732) {
			this.y = 2732;
			this.velocityY = 0;
		}
		if (this.x < 0 || this.x > 2048) {
			this.velocityX *= -1;
		}
		if (this.velocityY >= 0) {
			this.jumping = false;
		} else if (this.velocityY < 0) {
			this.jumping = true;
		}
	};
});
var Platform = Container.expand(function () {
	var self = Container.call(this);
	var platformGraphics = self.createAsset('platform', 'Platform', .5, .5);
	self.speed = 5;
	self.move = function () {
		this.y += this.speed;
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	stage.on('up', function (obj) {
		if (dragStart) {
			var pos = obj.event.getLocalPosition(self);
			player.setJumpForce(dragStart.x - pos.x, dragStart.y - pos.y);
			player.velocityX = player.jumpForceX;
			player.velocityY = player.jumpForceY;
			dragStart = null;
		}
	});
	stage.on('move', function (obj) {
		if (dragStart) {
			var pos = obj.event.getLocalPosition(self);
		}
	});
	var platforms = [];
	var ground = self.createAsset('ground', 'Ground', 0, 1);
	ground.y = 2732;
	ground.speed = 5;
	ground.move = function () {
		this.y += this.speed;
		if (this.y > 2732) {
			this.y = 0;
		}
	};
	var player = self.addChild(new Player());
	player.x = 2048 / 2;
	player.y = ground.y - player.height;
	var firstJump = false;
	for (var i = 0; i < 5; i++) {
		var platform = new Platform();
		platform.x = Math.random() * 2048;
		platform.y = i * (2732 / 5);
		platforms.push(platform);
		self.addChild(platform);
	}
	LK.on('tick', function () {
		player.update();
		ground.move();
		for (var i = 0; i < platforms.length; i++) {
			if (player.intersects(platforms[i]) && !player.jumping) {
				player.y = platforms[i].y - player.height;
				player.velocityY = 0;
			}
		}
	});
	var dragStart = null;
	stage.on('down', function (obj) {
		dragStart = obj.event.getLocalPosition(self);
	});
});

===================================================================
--- original.js
+++ change.js
@@ -13,10 +13,15 @@
 	self.update = function () {
 		this.x += this.velocityX;
 		this.y += this.velocityY;
 		this.velocityY += this.gravity;
-		this.velocityX *= 0.98;
-		this.velocityY *= 0.98;
+		if (this.jumping) {
+			this.velocityX *= 0.98;
+			this.velocityY *= 0.98;
+		} else {
+			this.velocityX *= 0.98 * 5;
+			this.velocityY *= 0.98 * 5;
+		}
 		if (this.y > 2732) {
 			this.y = 2732;
 			this.velocityY = 0;
 		}