yeah, allowing you to change the cards you played in the same turn you played them is high up on the list of things I would change if I work more on this. Thank you for your feedback.
How would multiplayer even work? Multiple players building a dungeon and then the heroes going to only one of them decided by some sort of factor? Then you'd need an incentive to attract heroes, because currently all they do is beat up your rooms. :D Or were you thinking more along the lines of one player plays the heroes, one plays the boss monster?