So I actually played this one much earlier in the week, but I forgot to leave a comment. I've replayed the game today, so I can give some up-to-date feedback.
The game has a lot going for it. I liked the gun sound effect, even if it did get extremely annoying after a while. The encounters in the game were actually quite interesting (Damn do I hate headcrabs) and the enemies are quite well done.
The NPC always gets in the way, which is perfect considering the jam we're in. It feels like playing a really bad half-life mod, but with some entertaining parts to keep you interested.
Overall, this was a great attempt, and it's not often you see source games at jams. Really well done!