I'm probably beating a dead horse here, since I'm sure I'm not the only one who experienced this, and I'm fairly late to the party after not having played for quite some time. So...
Is it just me or is the pathfinding AI for the enemies and your teammates absolutely horrendous during the festive event stages, particularly the Halloween one? I find it incredibly frustrating that sometimes the gameplay just devolves into hide and seek to find that one enemy lingering around and stuck on level geometry somewhere, because if it isn't killed, the next lot of enemies just don't spawn. I even got stuck looking for an enemy for so long that the game just triggered a failsafe condition and cleared the entire level for me even though I had made good progress and was aiming for that last wave bonus.
I also find the Halloween level to be so implemented so incredibly lazily that enemies just outright spawn in your face without the slightest bit of subtlety. I mean, it's sometimes fairly obvious the game spawns in enemies as you walk past certain trigger points on the main levels, but the Halloween level just screams 'we don't really care if you see them spawn in or not because we just wanted to push this level out'. I have a fair bit of completionist tendencies in me, and I can't say that having to play through these levels multiple times to buy all the festive cosmetics is generating a whole lot of excitement in me.
This all kind of speaks to me of ZERO QA testing, since an incredibly easy fix would have been to add clipping around complex geometry (a circular wall or platform around some of the tables, for example), which would prevent enemies and allies from getting stuck.
TL;DR: I found the festive levels, particularly the Halloween one, to have horrible pathfinding AI for enemies and allies which created a frustrating experience.
