In general, the version starting with a leading 0. until the full release would be better since it clearly communicates that it's pre-full release - since alpha/beta might just refer to the particular update being alpha/beta (not uncommon to have alpha/beta branches of updates for testing/early adopters while having a stable branch for most, both pre-full release and after), and Demo can also refer to the limited, freely available demo version coexisting with the full release (that has to be bought/pirated).
On the other hand, since you've already used v1...v8.2, switching to v0.9 (v0.9.1, v0.10 and so on) would probably cause more confusion than it solves.
On the other
other hand, the game does not have the Completed prefix and people here should be familiar with the Patreon model of incremental releases, so no matter the versioning and labeling used this is primarily a user error.
Edit: I guess you could something along the lines of "Game is currently in development, this is an incomplete early access version" in big letters to the OP.