1 hour ago, theFlu said:1.0 has traditionally meant feature-complete, and beta-tested.
Not in the world of software. Depending on design rules or philosophy it means entirely different thing (https://en.wikipedia.org/wiki/Software_versioning). Often the first number means major release, and the number after the point means minor release, without any connotation of "feature-complete" or "beta". People sometimes designate the first public release as 1.0, some don't. Inkscapes (https://en.wikipedia.org/wiki/Inkscape ) first public release was 0.35 , version 1.0 came 16 years later and was nothing special. Some people designate it as feature-complete like you said, some don't. For some 1.0 means having a stable public API. ...
And specifically in game software historically version numbers were not published at all. After the next game in a series came out you usually called the first one xxx 1 and the new one xxx 2, but it wasn't like the publisher put a 1 behind a game like Baldurs Gate. The first one was simply called "Baldur's Gate", the next one "Baldur's Gate II". And you would find out internal versioning numbers only if there were patches after release. Again they might have called the release version 1.0, they might not, it was an internal number anyway.