Game Invaders

Entry for the Ludum Dare 49 game jam. The theme was: Unstable. Can you help me defeat this bugs and release a stable version of my game? Its really unstable right now and I need your help. If you can beat the 12 levels without dying you would be my hero! Movement: W A S D Fire: LMB or Spacebar (click or hold) Collect the presents to increase your score and powerup your weapon and avoid the errors to not crash the game!