http://www.techspot.com/reviews/games/quake4_preview/QUOTE
One of the most talked about aspects of the Quake 4 demo was about the Strogg, which aren't known for humane treatment of marine prisoners, and this is clearly evident part way through the game. Kane's unit is completely devastated and he ends up being captured. The game cuts to Kane waking up on a conveyer belt that leads victims through a process which "stroggifies" the soldiers. Players get to watch, in first-person mode, as the marine ahead of Kane gets his legs sawed off and replaced with Strogg parts.