Ok first, do you mean the website of the japanese uploader (from here on out refered to as Zell) or their
You must be registered to see the links
page?
Better to just stick to
You must be registered to see the links
.
Zell had a blog but the site is gone and shouldn't be visited no more.
Second the engine used by Zell was very limited in size.
They had to split the game into 2 before they stopped development to find a better engine to make the game in. (those being version A and B)
They started development again last year which we are referring to as version R now.
Don't worry, there is not right or wrong versions, A and B are just the old but more complete versions while R is the remastered and currently in progress version.
Which you play is up to you as there isn't an overarching story or anything deep but if you wanna play them in order start with A than B and lastly R.
Latest version of A is 1.20 and B is 1.05 while R is updated regularly every end of the month so just check their
You must be registered to see the links
for updates.