is the full game going to available on gog.com or itch.io? I'd like to be able to legally back it up.
basically it just means I'd be able to put it on a physical disc for back up. Steam has a digital code so that you have to play it through the steam app. There isn't a way to download to put on a disc for back up. You would need the internet to play. For instance Sony is going full digital. If for some reason they decide not to host a game for some reason and take it down. You wouldn't be able to play it at all anymore. Steam is the same. If for some reason you took the page down for nymble 2. The people who bought it would no longer be able to play.
Oh! I wasn't aware of that. Nymble 2 is just a single-player game, so it shouldn't require an internet connection to play. I could be wrong, but to my understanding and a Google search, a game that's delisted on Steam will still remain in your library.
If it's any reassurance, I don't think I'd ever have any reason to remove a game from Steam, since it doesn't really cost me anything to keep it up there after the initial registration fee.