Mars Defender Lite: 3D Asteroids is a very interesting game. In it, you pilot a ship that has to defend the planet Mars against asteroids of all sizes. In some of the missions, you will have to orbit Mars to keep it safe, but in others, you will have to leave Mars' orbit and escort trade ships that come from Earth.
The graphics of the game is OK. Honestly, they are not the best graphics you have seen in a game, but the game makes up for that with excellent controls, a great variety of ships and interesting missions.
The controls are simple. You move your ship by using the left and right arrow keys and you activate the thrusters with the up arrow key. When you activate the thrusters, the ship will move in the direction that it is facing. Remember there is no gravity in space, so you can't maneuver easily. You have to time thrusts to move in the direction you want. The asteroids move fast and take orbits around mars, and you have to be careful to destroy them with your cannon when they are moving away from the planet.
When you complete a few levels, you will be able to use new ships. They are faster, more powerful and maneuverable.
In short, Mars Defender Lite: 3D Asteroids is a very interesting game for the Mac. It is simple, yet very challenging.