Loved it. Silly fun. The opening chat set the scene - I didn't understand any of the in-jokes, but I can appreciate why they were there - I liked the random documents you find.
I get the choice of weak guns > strong guns, and while I really disliked the pea-shooter at the start, it definitely made the shotgun etc feel "worth it" and better. Nice sense of "character getting stronger".
Penguins.. like. What? Great fun :D
Things I would have liked (in case you have any plans for further development and/or care about my opinion):
- some parkour over the desks/tables etc,
- some melee attacks
- maybe being able to throw stuff at the penguins (chairs, baskets maybe?)
- Some indication of enemy health? (I don't recall seeing anything other than the fun bin-hat)
- Minimap maybe? would be nice... I got so (so) lost all the time.
- Maybe some control over the intensity of the head-bob camera movement? It felt pretty cool but was a little heavy.
All in all, yeah - very cool, good job ;)