Thank you so much for the feedback!
Regarding the models, I'd need a bit of research into free models available, as art is mostly out of my reach. About the sound, I tested the online version and it somehow started with music and effects volumes zeroed, don't know why yet.
I plan on giving a few more abilities to the player (like invincible dashes, better guns) and add some boss encounters after x minutes. Did you find the texts readable enough?