Wow, very cool! You even made an icon.
Making an FPS in 48 hours is a huge achievement and having actual combat is even more impressive.
The middle of the crosshair doesn't line up with where the shots go, they fire towards the upper corner of the sprite. That's fairly infuriating ;)
I'm not sure having a timer works for this style of game.
Graphics are very good and the music is catchy in a repetitive way.
Good work!