A really nice D&D 'implementation' is Lamentations of the Flame Princess, at least in terms of the supplements, particularly Zak Smith's stuff. The last time I

A really nice D&D 'implementation' is Lamentations of the Flame Princess, at least in terms of the supplements, particularly Zak Smith's stuff. The last time I played D&D was during the 2e era (though I stubbornly stuck to 1e), and the LotFP has some of the flavour of the good I remember from that time (with its own twists).