Right now I'm trying to get a return on
Arma2 because it's an old game and the Steam browser, the list of servers for this game no longer functions within Steam. This was the case when I first cranked up the game. My argument is that I purchased this gema throuh Steam specifically to run via Steam. At first they said no, but then wanted a copy of the email I got from the developer saying that vanilla Arma 2 in-Steam browser no longer was functional. Waiting for a final decision.
I believe my point is a valid one...
----------
A purchase on Steam allows you access to download any version of the game that Steam carries. As said, when browsing games if they are Mac compatible there will be a Mac logo by its title in the browse/purchase list.
Some Steam games will play in offline mode.
https://support.steampowered.com/kb_article.php?ref=3160-agcb-2555
I use Steam, it offers a lot, it's advantage is that it offers an interface where Steam users can coordinate their efforts, communicate, and play/join each other's games when multiplayer is a component of the game. However if the same game was available on gog.com, I would consider that instead, among other reasons, an actual return policy.