the glitchy screen effects were a nice touch.
I didn't quite understand the how upgrade system worked though.
Viewing post in Lost Frames jam comments
I'm not sure what you mean exactly by how the upgrade system works, so let me explain it in more detail.
Every time you clear a room, two random upgrades spawn: +Max HP, +HP, +Attack Speed, or +Damage. (That's all the actual upgrades)
Once they appear, you have to walk up to the one you want and press F, as shown below the rewards, to pick it up.
Hope that clears things up! Thanks for giving my game a shot!