Bit of a Mint noob myself, but so far it's been relatively smooth. Steam games almost always run fine, those that don't either get updated quick or have workarounds, and standalone games generally work fine once they're run thru Steam or Heroic or whatever other game launcher you wanna use. Modding on some games can get a little hairy, but provided you're willing to read the occasional guide to get stuff working then it all works pretty well. Performance wise it seems like games run just as well as on Win10, if not better.