Those are some really good ideas. I do want to add different types of enemies and Korra from Avatar would be fun! Let me see what I can do for the next update. Thanks for the feedback!
when do you expect to release the next update, or do you not know?
Also, I have a couple more ideas: an enemy type that moves 1.5x as fast, but instead of damaging, they just disable/put on cooldown the hit heroine's power. Or, an enemy type that damages a random heroine if you touch it with your mouse (or maybe only when you're not using a power if that's too OP).