A fun and refreshing concept! I think this game would have a lot of potential with some polish! Great work

What I liked:

- The concept, very fun and interesting

- Gameplay, the fast forward feature is a great add! How you fight as the Boss is interesting too!

Things I'd Tweak:

- Add the ability to resell monsters or traps (or undo at least), I accidentally placed stuff a few times and wished I could fix that.

- The ability to heal after each hero defeated! The way I would do it is give the boss Purple hearts, each time you defeat a hero you are healed 25% of their total heart value (Purple Hearts on them would indicate how much you'll heal). That or you can buy hearts at the cost of gold.

- A special attack that recharges overtime or a number of heroes defeated. It'd be useful if I was hurt or a hero was really strong.

What I'd add: 

- The ability to see the hero's path and how what you place affects it. Would help Players plan more.

- Random Rooms, I think it'd add a lot of replayablity if rooms were random.

- Mini Bosses, these guys would be expensive but could be useful wearing down the hero.

Treasure Chests, these would be a great way to make the hero break off the beaten path to you, you could line the room its in with traps! Could also add mimics too with that.

- A Boss Key! A high priced item that would force heroes to search rooms for it. Add the ability to hide it inside treasure chests (or mimics he he). It would only appear in the last chest in a dungeon that the hero opens.