You are Kal Solar and your mission is to land on the planet Xelos where the crew of the station Alpha II have been massacred by some mysterious alien force. Aliens are multiplying like galactic rabbits (!), stealthily spreading their eggs around the base (in places such as ventilation ducts and air conditioning corridors). The only way to stop them is to seal them inside their incubation areas and inject a deadly dose of cyanide gas. But you need also to seek and destroy the base's power generator that is tapping power from the moon's core, in order to make sure none of the eggs survive. Of course escaping before this thing blows is critical too. The actual complex is a huge place, with a number of dangers and problems to overcome.
Apart of the evil aliens, there are plenty of other nasties to worry about such as protector Droids that are completely out of control and will kill anything that moves.
Exploring Xelos can be done either by walking around in a space suit or flying over it in the Manned Maneuver Unit (MMU). There are a number of items to be found and objects to identify before you can hope to sort out the aliens. Kall needs to use all of his equipment to the full to safely explore the alien lair. Discarded items can be found all over the complex, and can be handy and useful at some point. At all times, you need to always check vital information for your oxygen, temperature and radiation levels in order to survive, and all the indicators (along with a compass and many others) are seen on the head up display of Kall's helmet. Infestation is pretty playable but also, a bit difficult to play. Remembering where you are going and what you have seen is pretty crucial as there is very little time (and oxygen !) to complete the mission.
As expected, graphics are pretty good, but not exceptional. They are not as superfast as Starglider 2, but they are very detailed and there are a hell of a lot of vectors on the screen at any time, moving quickly enough. The screen combines a nicely bitmap-drawn console with solid and flicker-free 3D to produce a tense, claustrophobic-feeling game. The Amiga version sports more than 32 colors on screen (when in the inner sectors down to the base). The opening scene is superb, a classic Psygnosis intro, in which an astronaut jets through space in fast, realistic perspective before landing to Xelos.
The eerie effects and intro music cap off the screen perfectly, producing a really atmospheric interactive sci-fi story.