about 4 years ago - Shurenai - Direct link
It's my understanding that, at least as it used to be before A19, that game difficulty affected your maximum gamestage- with the topmost difficulty being unlimited.

However as of A19 I believe they made it so game difficulty has no bearing on your gamestage.. Which may mean that, as it currently stands, you may be incapable of reaching 1000 gamestage in the current build.
about 4 years ago - Shurenai - Direct link
Either A18, or possibly A17 should(?) work. Possibly also A16..but I don't remember if versions before that had the gamestage mechanic build in yet.
about 4 years ago - Crater Creator - Direct link
Originally posted by Skyguy: Hmm, would reverting to A18 perhaps make it achievable once again?

I went much further back initially to give it a go, though I suspect the old survivalist achievement isn't compatible with the gamestage version of it so it never popped for me.

Yes, in general other users have had success reverting to earlier Alphas to get achievements that aren’t currently attainable.