What an incredible achievement! Making this kind of 3D game in pico 8 with only two buttons and directional movement seems like quite the challenge. The game works surprisingly well. I found the flickery wall sprites made my eyes hurt a bit after playing. I didn’t really enjoy the combat until my second play when I figured out “hold fire to strafe” (thanks to your gifs). After that, I got to gun 4 and really started enjoying combat (even tricky bits against high enemies). The final room was great – tons of power ups and less frustrating jumping than the earlier jumping puzzle.
Nice work!
One question: what is that constant bam bap bap noise? Sounds like an enemy is walking against a wall somewhere.