Dont' know about games, but certain apps you won't see on shield because they deem not compatible or something? But you can side load it. Maybe its the same with games?

Off-topic, but I wish Rockstar updated the games so they wouldn't crash every 2 minutes on newer phones.

Look for them in the Nvidia Games app.

Those games are not in the (Android TV) Google play store because they mark as incompatible with Android TV SO THEY EXCLUDED. GTA Liberty City Stories v2.2 is their if you search for it I just sideloaded it last week but it's available for purchase in the Android TV Google Play Store.