Free implementation of Heroes of Might and Magic II game engine based on SDL, under active development by fheroes2 Resurrection team. You can watch their annoucements here.
Build is available for Windows, MacOS and Linux. Technically you should own Heroes 2 or at least demo of Heroes 2 to playing it. Homepage of the project is https://github.com/ihhub/fheroes2
Sure, that you are welcome to playing it and comment, as well as, to contribute!