Interesting concept and good gameplay. It's great that you have included a tutorial, furthermore I didn't understand some concepts, for example, what does the flag do after discovering a mine?
Also, I would appreciate knowing the power of the monsters and its combinations (for example, after mixing two monsters, a panel reveals what they will become and its stats, and you can keep this info, so you will remember for the next time, :) I felt like a noob dying every time against the first knight. Maybe the difficulty is a little bit high (or I didn't understand everything).
Good job developing this game, I loved the way you merged different types of game in once. Keep rocking.