Took me a few tries to get back in the groove but it was smooth sailing after that.
The new rooms are nice, it's good to be able to put some obstacles between you and your enemies.
The minimap should show the direction to the exit after you've found it.
A "full map" button that only shows the rooms you've been in would be nice, that way the player can more easily make sure they've cleared the whole floor before going to the next one.
The miniboss dies weirdly while frozen, the dying animation slows to a crawl and the audio cue doesn't play properly. Maybe frost should defused it like the mine enemies.
Also I would make it so the last floor's ending portal is always behind a miniboss so that players have a final challenge to look forward too. It's a bit anti climactic to enter the last floor and find the exit after 3 rooms.
The new UI layout is nice but you've removed the "press C to open upgrade menu" text so players won't know that exists unless it's in the tutorial.
Taking your eyes off the character and your enemies is still dodgy to do in combat. I'd prefer if the chem stock UI was, like, 3 times as big and transparent, but don't do that because it would look ugly.
Really fun.
Looking forward to playing more and seeing new enemies.