Having imported save states from the previous version of the game, while on New Game+, when playing "The Face of Madness" on Extreme, I get at about half-way through the boss health bar and then it crashes. I've tried this at least 5 times and in each instance, it crashes at about the same time which means that there's probably an out-of-memory or stack-overflow issue, not sure.

EDIT: Info that might help:
I've tried this both in Fullscreen and windowed mode and while reducing the particle effects to 0%, reverting sprites and cutscenes to classic and removing flashes and the like.

My PC is a 1366 i7 Extreme 975 with 12GB RAM and an nVidia 580 with 1.5 GB VRAM on Windows 10 Pro x64

EDIT 2:
It appears the crash has nothing to do with the level per se but rather with long-drawn battles with many defenders and enemies on screen.
It just happened to me on Bonus Challenge 3 at about wave 35 or so.

At the time of the crash, RAM usage was at about 1.5 to 2 GB from about 200-300MB when I first load the game so it appears there's a memory leak somewhere.