Welp I got to level 4, and it got too hard for me. I really liked big the sprites were and how close up it felt, like I'm actually there.
Here is some critique:
1) fire sound is way too loud
2) would be nice to flip the pistol when you are facing left
3) player can shoot through walls - is that intended?
4) it would feel nicer if one could just hold down the LMB and the gun would just fire automatically