I actually enjoyed the movie. Though there were some errors (alien arms bursting through torso, size of marker, and the captains death) overall it was a good flick. Bought it the day it came out, next: ordering the graphic novel! (also rocks)
alien arms came through the stomach, which is the same in the game as well.
the size of the marker was about right when compared to the human size.
and the captain does die because he plays a significant part in all of it. in the game, there is even a video log of it.