Glad you like the game! I've not done an Android game before, but it is on my plans for learning, so maybe one day I'll port some of my older ones across to it, too.
If you want to donate, you can always buy the game again, and set your price. I assume? I've never tried downloading a game twice on here, but I guess it's possible. If not, I've got a (rather neglected) Ko-fi page here: https://ko-fi.com/estragonhelmer