Minus certain modes from Sm4sh, plus a few unique game modes, probably minus 3DS content. That is a brand new game. The only thing that will be absolutely familiar is the game engine, they're free to tweak mechanics, movesets, and animations however they please. If that's an "enhanced port," then Skyrim is an enhanced port of Morrowind. 5mash isn't even from the same developer as Sm4sh.