Great game and a cool genre-mashup (I have too many hours in Vampire Survivors...). The crawl gameplay was excellent and I really like the 3D pixel art. I enjoyed the chicken voice acting.
The Survivors gameplay was okay but I think there's some things missing. It should show the time remaining and how many kills before the next upgrade. It's also possible to kill all the monsters before the timer runs out and then you're standing around with nothing to do, potentially for quite a while. Either the sequence should end or monsters should be infinite. One time I also seemed to encounter a bug where a battle sequence never ended and I had to restart.
Really enjoyed this overall. I guess I'm not so great at finding the crystals though - I only got 5.