The game combines neon colors, simple graphics, and old-school sound effects with the iPhone's touch screen and accelerometer controls, creating a game that is both familiar and challenging.

The concept is simple: you're flying a spaceship, and you're being attacked by other spaceships. You tap the screen to shoot at enemies with your lasers. For every kill you achieve, you're rewarded with points that turn into cash you can apply to repairs, health upgrades, and fancy new weapons like missiles and bombs.

You maneuver by tilting the phone side to side and back and forth to align yourself with enemy ships. You also have two radar screens to see what's in front of and behind you, but otherwise the range of vision is very limited. Ships can approach and then retreat while you stay in a fixed position, so it's important to take them out when they get close.

Each successive level gets harder and harder as stronger, more numerous ships appear. There are 33 levels in all, making for some epic marathons if you've got the time. If not, Onslaught from Space will save your progress after every level.

The store aspect of the game is a good concept, although not all items are worth the money. Repairs and health upgrades make sense, but using the missiles I bought was a major hassle. Your available weapons are displayed at the bottom of the screen during gameplay, and in order to switch, you have to slide them over and select which one you want.