Glad you liked it! I enjoyed your entry as well, I liked the confusing geometry. My inspiration for the visuals largely came from games like Cruelty Squad and Ultrakill. For both modeling and texturing i roughly follow the limitations of the ps1.
Textures no bigger than 256x256, usually around 128x128. I use images sourced from the internet and cut them up and lower its resolution. There’s lots of free texture websites online. You can also source from your own pictures you take. The quality doesn’t need to be very good since you’re lowering it anyway. As for the crunchiness and colors i heavily edited these images in Krita before lowering the resolution. Changing the color balance, burn, contrast, kinda just doing whatever that made it super crunchy looking.
For modeling similarly i try to keep the poly count low, it’s generally a rule of thumb and not a hardline rule, I'm not too concerned with what could actually run on a ps1. No model here has more than 1,400~ tris though i don’t have the actual count in front of me currently. Limiting yourself here forced you to adopt the mindset of those modeling for the ps1. It can also be helpful to study models from actual ps1 games and see how they’re constructed. There’s lots of sites online with ripped game models to study.
And last i just have a simple psx shader, and on body parts i enable vertex wobble in the shader where otherwise it’s disabled.
Its mostly learned from PSX tutorials and stuff so if you like the look start there. It’s obviously a bit more involved than i was able to explain here but that’s the general mindset and process.