Thanks for the honest review.
I had some problems when I was working on the game that I didn't have enough time to work on the balance. The problem is not due to the abilities exactly, these are because of something small that I added that turns out to throw off the balance a bit - the increase in passive damage is higher than the increase in the HP of the enemies, causing this result. I plan to completely lower the light/plant damage increase or at least moderate the increase.
I also know this problem. I personally have no idea what causes it and I try to get frustrated about it when I have the time. But I'm glad that all in all, with all these things, you enjoy playing :)