Ever played Space Invaders and wished you could have more than one ship, each with different types of lasers that could destroy rows of invaders in one go? Now you can. You can build as many ships as you can afford, which will try and shoot down the rapidly descending invaders.
Different types of ship are available, including pulse laser and zappers, but there are also different types of Invader trying to destroy your towers. You must destroy them all before they reach the bottom to proceed to the next level, where more and harder invaders are waiting!