Fun concept, gets a lot more interesting on the 2x3 box level so feels like it would keep scaling well. Feels a little too easy to keep the skeletons away with the one turn cooldown on the 1 attack, means the other attacks don't get much use. Also feels weird having the key for the 4 tile be 2 when you only have 1 and 4 available, I think it should just be the number itself as the key, if that makes sense.