text: ENGINE.Bullet = function(args) {
  
    Utils.extend(this, {
  
      direction: 0,
      //speed: 300,
      lifespan: 2
    }, args);
  
    this.radius = 9;
  
  };
  
  ENGINE.Bullet.prototype = {
  
    constructor: ENGINE.Bullet,
  
    zIndex: 3,
  
    collidable: true,
  
    collision: function(entity) {
  
      if (entity.hit) {
  
        if (entity.team !== this.team) {
          entity.hit(this);
          this.collection.remove(this);
        }
      }
    },
  
    step: function(delta) {
  
      /* lifespan */
  
      if ((this.lifespan -= delta) < 0) this.collection.remove(this);
  
      /* movement */
  
      this.x += Math.cos(this.direction) * this.speed * delta;
      this.y += Math.sin(this.direction) * this.speed * delta;
  
      /* wrap */
  
      app.game.wrap(this);
    },
  
    blueBullet: [20, 53, 6, 6],
  
    redBullet: [43, 53, 6, 6],
  
    render: function() {
  
      if (this.team) {
        app.layer
          .drawRegion(app.images.spritesheet, this.redBullet, this.x - 3, this.y - 3, 1);
      } else {
        app.layer
          .drawRegion(app.images.spritesheet, this.blueBullet, this.x - 3, this.y - 3, 1);
      }
    }
  };