Hey there Loud Crash Test,
Great name :P. Thank you for the support!
The extension roadmap is a plan to “finish” the original game, as it was left in an incomplete state.
The remake is absolutely free, so you don’t have to feel the need to buy. The donations serve mostly to ensure we can buy CGs to add content to the game, as CG work is very expensive. It can also help us to buy one or another lunch, but we don’t get that much, so most of the money is being saved for CG commissions :).