Planet Stronghold 2 ? A lame adult game, there's less to see than in a Mass Effect game, which clearly was the inspiration. But the story by itself is good and the game mechanism are a must see for all those who think that Ren'py should be limited to Visual Novels. It's one of the few games not made with RPG Maker, that can really be defined as being RPG.
Else you've games like Sakura Dungeon, by example, but they are not this much on the leveling side.