Re the versioning.
Most devs get this wrong, simply because they don't actually have a development road map and this leads to blind guessing where the number should tick over. The only way you know you have completed the game (Version 1) is if you have it detailed what features should be in the game. With the third or fourth ticking over whenever there is a bug patch...
Too many Dev's seem to think that because they no longer wish to work on the game that it is worthy of v1 even though character stories may or may not be completed. Think of a tv-show that was cancelled mid way through the season and no one being allowed to tie any loose ends up.
Still if this dev is using v0.6 to mean 60% complete as I suspect they are doing, then they're probably not far wrong (imo)... I saw a decent amount of content in there.
There isn't a real standard and it's more of a loose guideline to be set by developer preference, reading the changelog is a better indication of what was actually added.
Since so many people cry fowl about the dream of 1.0.0 the first slot doesn't get used for anything.
While the second slot generally is reserved for big updates, Arc mostly counts up from 0-9. So it doesn't really represent anything more then 10 weeks in.
The third position is revisions so bug fixes usually go there but since this is mostly used as a weekly counter that tends to get neglected. On the off chance he actually does release a bug fix it gets appended as abc.
The counting up 0-9 could be some people see decimal points and assume it's like regular math but in reality you could have version 0.9999.9999c (remember people will cry if the first slot is ever used
)
So while it's nice to dream that this is a percentage complete it's in actuality a weekly counter. Some weeks are more meaty content wise then others.