ScrollingTower_2_Update

    override public function update():void
    {
        super.update();
        // For movement direction
        var movement:Point = new Point;

        /**
         * Vertical movement
         */
        var tempY:Number = y;
        // Check ladder collision (to climb up/down)
        if (this.collide(Ladder.TYPE, x, y+1) || this.collide(Ladder.TYPE, x, y)) {
            if (Input.check(Key.UP)) movement.y--;
            if (Input.check(Key.DOWN)) movement.y++;
            v.y = SPEED_X * movement.y;

            // Update Cordinate Y
            tempY += v.y;

            // align to ladder after climbing up
            if (!this.collide(Ladder.TYPE, x, tempY)) {
                if (v.y < 0) {
                    tempY = Math.round(tempY);
                    while (!this.collide(Ladder.TYPE, x, tempY)) {
                        tempY++;
                    }
                    tempY--;
                    v.y = 0;
                }
            }
        }

        if (!this.collide(Ladder.TYPE, x, tempY)) {
            // If no ladder, affected by Level.GRAVITY
            v.y += Level.GRAVITY;
            if (v.y > Level.MAX_Y_SPEED) v.y = Level.MAX_Y_SPEED;

            // Update Cordinate Y
            tempY += v.y;

            tempY = Math.round(tempY);

            // avoid going through a ladder when landing on it
            var landingLadder:Ladder = this.collide(Ladder.TYPE, x, tempY) as Ladder;
            if (landingLadder && v.y > 0) {
                tempY = landingLadder.y - this.height;
            }
        }

        tempY = Math.round(tempY);

        // Collision
        if (collide(Block.TYPE, x, tempY)) {
            while (collide(Block.TYPE, x, tempY)) {
                if (v.y > 0) {
                    tempY--;
                } else if (v.y < 0) {
                    tempY++;
                }
            }
            v.y = 0;
        }

        y = tempY;


        /**
         * Horizontal Movement
         */

        // Detect key click
        if (Input.check(Key.LEFT)) movement.x--;
        if (Input.check(Key.RIGHT)) movement.x++;

        // Update Horizontal Speed
        v.x = SPEED_X * movement.x;

        // Update Cordinate X
        x += v.x;

        x = Math.round(x);

        // Collision
        while (collide(Block.TYPE, x, y)) {
            if (v.x > 0) {
                x--;
            } else if (v.x < 0) {
                x++;
            }
        }
    }