I remember there was a bug on the App Store that cause some issue on certain games. I posted on the thread "Why not buy this game on Steam instead. It costs the same, doesn't have this issue, and you benefit from the game working on Windows/Mac/Linux at no extra charge. You also get proper trophy support, cross platform multiplayer etc..
I got a bunch of 'Why on earth would I do that. I love the app store and will only ever have Macs.'
Steam has its own set of issues where they control what you get to play, and when.
I feel like I've "bought" a ton of games through Steam, and now that my kids are a bit older, they want to play some of them. Unfortunately they can't play different games at the same time - even with Steam's family sharing. When one person plays a game, it locks the whole game library.
I got a bunch of 'Why on earth would I do that. I love the app store and will only ever have Macs.'