I was a bit lost at the beginning, not really knowing what to do with the dead enemies after each wave. It was only after pressing H and reading the instructions that I figured out I had to use keys 1, 2, or 3 on the bodies. Then came the second challenge: understanding how much each action costs. If I could give you one suggestion, it would be to improve the UI, because I found it a bit unintuitive.
Maybe you could add icons to the dead enemies showing the available options: 1 to revive, 2 to turn into a tower, and 3 to absorb. Another possibility would be to limit the available actions depending on the enemy. For example, some could only be revived, others turned into towers, and others absorbed. I think that could make things a lot easier to understand.
I really liked the art! The necromancer looks really cool. I don't know if you generated it or not, but it turned out great. I managed to reach wave 6 and beat the game. For me, the most fun part was carrying towers and enemies around from one place to another. I think it's worth exploring that mechanic further because, in my opinion, it has a lot of potential.
Anyway, good luck with the project!