As long as you're an active Patron at the time and have donated $10+ or more, you'll be guaranteed a DRM free copy of the chapter on release. Since I'm still growing and have few enough Patrons to manage, I may be able to backdate whoever has donated $10 or more in the past and give them a copy, too even if they weren't still currently pledged, but the more things grow the more difficult it might be to manage that.
And to clear up any confusion, DRM free simply means it's a download of the game you download, and then can run without needing any kind of password/account like steam or anything.
If I were to go back on previous chapters and enhance them, I would probably do that when the full 'story' is complete and I merge all the chapters together into one game and polish it up here and there and tweak some things based on feedback to create the perfect story at the end of it all.
Only time will tell how well the overall Patreon will do over the months! I'll just have to keep consistent with my progress and continue to deliver updates that people are happy with in order to sustain growth, or at the very least keep the people I have happy~
I have a rather large planned out story that will unfold over the chapters, so fear not. I've put a lot of thought into how key points will go down, even if Chapter One doesn't seem too 'grand' and focuses largely on a small amount of characters, it'll still lead into bigger things, I promise!