A solid entry with good mechanics and a lot of verticallity.
Decent ambient music and sound effects and good movement but I am more used to "Q" and "E" for turning not strafing.
There where some instances where I was floating in mid air (with no ladder).
It looks like using a health crystal triggers a respawn of the enemies, I got stuck in a "slay bats -> use crystal" loop until I realized this.
Nice and enjoyable jam entry.