Nice game, i'm curious about how the polygons of the model animated move like that, is like ps1, probably is something in Godot. Funny game.
I used a shader to create the vertex snapping and texture warping effect like a PS1 has. It also has simple cel shading. I lost the exact shader I used in the game, but it was pretty simple to recreate, here's the shader: https://pastebin.com/YScpc7dv