The new Tower could be the basis for a cool twist on the alpha's Gauntlet mode - instead of repeating the same dungeon over and over at a higher difficulty level, you go down (up?) an endless series of floors, each getting progressively harder, with the goal being to reach as low (high?) a floor as you can. Possibly disable the ability to return to previous floors for that authentic roguelike "iron man" experience. The game could track record your best performance by class - e.g., "You've reached floor 58 as a Rogue! You've reached floor 41 as a Sorcerer! You've reached floor 13 as a Berserker!"
EDIT: Forgot what I even meant to write this post about in the first place. This is how fast regen and poison appear to be interacting now: fast regen causes a monster to heal 2x their level in HP per tile; when poisoned, a monster with fast regen heals 1x their level, which is exactly what they would recover if they had neither fast regen nor poison. Is that how it's supposed to work? In that case, you may as well disable poison altogether on those monsters, because it's pointless to do so in 95% of circumstances. (And the 5% where poison would still be useful is so niche and counterintuitive - e.g., purely to get piety from TT - that it's not worth retaining, IMO.)