Very nice! The game was very fun and highly impressive for just 48 hours. It really could have benefited from SFX though — at least basic sounds like those you can make with SFXR. Music would be nice too. Another suggestion is to make the player hitbox smaller — I kept hitting into walls when visually I wasn't touching them. Also perhaps a circular hitbox would have helped because then you could "slide" past corners which would feel a lot better. A slight camera shake too on bullet hit would be nice. Finally, you should make the door opening and closing use the inventory key instead of the shoot key, since I kept going inside when I meant to fight.
All in all, very nice! Could make a very good game when fully fleshed out. Congrats!