Hi there.
First, I really like a lot about this game. Nice 2D graphics, fun and challenging mechanics. Not just another griding game (boring).
However, I don't like how saving works. I think the game should save at certain spots in a way that you cannot abuse the system. Right now, it saves every time you go down/up stairs. But it should really only save one time per floor level. Like a single use check point. Right now you can save mid level. It takes some of the challenge of out of the game.
I would also like to see a hardcore mode in which the game doesn't save except on art change. If the host crashes in coop another PC makes host automatically (so a player can rejoin). This makes the game a lot more satisfying to make runs at if you have the time available. Every death matter now.
Point is, make every death matter = high risk, high reward. Single runs that can result in total defeat can be a lot of fun for an extra challenge and thus much more satisfying when you succeed.
What do you guys think?