Note that before playing for the first time, some titles may require you temporarily adjust your security settings in System Preferences > Security & Privacy > General. These aren’t just casual or hobbyist games, either, but full-blown, high-quality gaming experiences. Indeed, the Mac App store is positively packed with free games, and you can pick up some amazing Mac games elsewhere that are great fun to play without paying a penny. This is a shame, because the Mac is a great games platform with plenty of excellent freebies.
Apple fans are used to free gaming for the iPhone and iPad, but tend not to think so much about free games for macOS.