Hi this is cool and a lot of fun with really great graphics! I think there are two things that could really help make this a fantastic game. The first would be giving a reason for the player to not just build corridor style dungeons (I found myself just b-lining it to the boss room.)
The second is I think it's a bit tough, I think the enemies could have less health. Also lowering this challenge would incentivize me to attack more enemy rooms rather than the minimum required.
This is a great game overall, and very fun. Congrats on submitting!