I actually like the graphics somewhat even though I normally dislike pixellated graphics. It definitely could use more details though (like posters, plants, stuff that you can find e.g. in Wolfenstein 3D too). Also weapons really need to be less pixellated, e.g. like this http://cdn.akamai.steamstatic.com/steam/apps/2270/0000002417.600x338.jpg?t=1342306398 . And enemies too (e.g. like this http://gamecenter.nyu.edu/wp-content/uploads/2010/03/3413-doom1.jpg ).

What is up with the windows cursor floating all over the screen? Better to hide that. (yeah sorry I refuse to play a shooter without a mouse )

Also some doom or wolfenstein 3d like music would be nice as background music.

Good start I would say.