I found a couple of bugs in the last level on Insane mode
1. Sometimes when there is a lot of units on the screen (or animittion) the game will be slowed and the character will not do what you say.
EX. You clicking on a group of mages instead he goes into the lava.
I found myself dieing ALOT because of this.
2. Sometimes when there is leftovers from the last level the come to bite you in the ass once you respawn.
EX. I had just respawened and four shriekers and a gang of skeletons appear out of nowhere.
3. If number two happens the game will think your always in Fitnesse class. Also if you try to change it you cannot use your spells. (You still get your stats though)
EX. I had picked Range and instead of a shockwave he just dashed and jumped.
I hope these bugs get fixed soon they would help a lot.