thanks a lot for the answer!
I think I agree with you that it's too easy - I didn't have enough time to check the balance unfortunately and this is the result and I thought to myself - hey! Why don't I give the enemies life every 3 turns and the "plant" (that's what I called the ball of light) for 2 waves 1 more damage.
It affects too much it turns out. This is a mistake on my part. I'm glad you enjoyed my game!