First, thank you for your detailed review! For my first "real" jam ever, it's nice to see that my concerns were also noticed by another player/developer. Yeah, by the end of the week I noticed that the enemies were getting stuck when colliding with each other, but could not find out a way to fix this (maybe the static navmesh is a problem, a dynamic navmesh would solve it? I really don't know).
My ideia was that at each five waves, you would find a boss, but my lack of game development experience made me uncapable of finishing even the first boss (but currently still working on it).
I will also experiment with the idea of automatically picking-up the weapon when running over and will adjust the attack range and animation (never did animation in my life, and that one for the attack is terrible).