Radiant

Radiant is a very good space action shooter for the Mac. It looks a lot like Galaga, but with better graphics and a nice weapons system.

In the game, you have to shoot down enemies that appear at the top of the screen and move around. They will try to either shoot you down or collide with you to destroy you. Your ship is fixed at the bottom of the screen. You can only move left or right. This is why the genre is called fixed shooter arcade.Your ship fires automatically, so the only two controls that you have to worry about are the left and right arrow keys. When you shoot enemies down and when you collect the little "$"s that fall down from destroyed enemies, you are collecting points. The enemies come down in waves. After 2 or 3 waves, the game gives you a chance to purchase new weapon systems with the points that you have collected. You can switch between them in-game by clicking on your ship and selecting the one that you want.

There are three game modes: Casual, Survival and Hardcore. There are also tons of levels and different types of enemies. Some of the boss fights are very hard to complete on the more advanced difficulty levels.