Hint: Assault Training
In the training level, when youre finished with the handgun training and the solider tells you to go back through the course (this time with a gun) don't immediately go through the door. Instead, go back up to where you first entered the level, all the way to the end of the hall to locker room. There will be an assault rifle laying on the floor.
Easter Egg: Credits
In Starke's apartment change the channel on his TV to see the game credits.
Hint: Speed Up Decontamination
In the Experimentation level you will find a decontamination room with the door locked. If you want to open that door you need to use Telekinesis in one fan behind the cristal in the left of the door to accelerate the decontamination process.