Earth Impact Mini Game: The Reliance mini-game is hidden on level 8 of the Reliance level. Go to the building on the right and enter it through the vents. At the room where a guard is playing one of the Arcades kill him and use the Arcade he was playing. The games High scores are tracked in your statistics menu and when you have unlocked this mini-game you will always be able to play it by pausing the game.
X-Space '92 Mini Game: In the Madness level there is a hidden floppy disc which you can use on any computer on the level to play (the nearest computer to the disk is the reception computer). To get to the disc you have to go just past the reception desk section then through to the right and in the center of the corridoors with all the mental patients there is a room. Inside the room is the shotgun and on top of one of the shelves is the disc. You will have to use Telekinesis to reach it. The high scores are tracked in your statistics menu.