As you progess level by level, the ship increases it's number of arms, it's speed and it's armour becomes stronger. Your main problem is cannonfire from the mothership although there are also obstacles such as meteors and planets to avoid. What you really notice with this game are the sound and visual effects which are really explosive for such a tiny game. However, once you've gone through 5 or 6 levels, it really get's a bit too hard and you'll have to spend a fair few hours on this to complete it. It's great for releasing stress anyway!