INTRUDER ALRET!!
This was seriously neat! I enjoyed plenty. I'm actually wondering who the intruder was? I'm going to jump on ledge here and take a wild guess. Is it the computer? One of those A.I. system gone horribly wrong. Like HAL 9000 from "2001: Space Odyssey"?
The sound effects were awesome, whether or not they were taken from Half-Life 2. Although animation wasn’t great it was still very cool.
Keep it up man.