Which games couldn't you play from GOG? Heroic does its job very reliably for me. Basically eveything I throw at it runs. Witcher 3 (even the new remastered Version), Deus Ex: Mankind Divided, Baldurs Gate 1, Arx Fatalis, System Shock 2, Syndicate, old Ultima classics (like e.g. Underworld) etc. Even modern games from Epic seem to pose no problem. Achievements get synced to the GOG cloud usually. Only thing I am unsure is which games sync their savegames to the cloud. So I back up all the savestates regularly.