It looks like most of the bumps in the version numbers of the specific games that I have installed are
just adding or updating the languages translations.

But after tinkering with the game-launcher Athenaeum for a few hours, I do not yet understand
it very well.

There is an "Update All" feature in the menu, and it goes to the various flathub repos and updates
the game.    ( And it displays a silly message that is different each time you update, For example, "Ringing Cowbells".  
   For example, Minetest game is updated to the June 10th version and most of the Gnome games
are around March, 2020, and most of the other games I have are late 2019 versions.

But Gnome software is confused about that for some reason.

I think what I am saying is that if you have to have the nightly version of the game, then don't use Athenaeum
as your game-launcher.

But if you want to easily scroll through a list of 100 installed games, the games do launch quickly.     I guess
Athenaeum would be something to put on a kid's Linux computer.

David Locklear