Great game but some suggestions.
First, I really liked this little game. I thought that overall, it was really well done. I thought that the gameplay was great and the graphics were also well done. I also think that it is really cute and charming. I can definitely see the Quake influences.
Second, here are some suggestions I hope that you take into consideration.
1. Add a borderless windowed option maybe with some custom resolution settings. I know that you have a 64kb limit, but I think that this would be a really nice feature.
2. Add a save/load game feature. Not totally necessary, especially since the game is only 4 levels, but it would still be nice.
3. Less obvious but don't place ammo and health pickups near important items like switches. I might only need 5 health or ammo when I need to use the switch making the pickup kind of worthless at that point.
Finally, I am glad that you didn't add too many enemies when you ascend/descend lifts. One of my peeves is when an author puts too many enemies when you get off a lift making you have to jump back down to deal with them better. Thank you for not doing that.
Thanks again for making this cute and charming game.

