i work on a free super mario 3D clone called Monkey World 3D, i use bge for that

here is the download-link for that

http://platen-software.de/sebastian/monkey_world_3d_v01.zip

i used different art here from oga: a lot of free textures and some models (see readme-file)

Someone tried that some years ago (Supertux 3D)
see here: http://sourceforge.net/projects/supertux-3d/
but the developer stopped the development of this project some years later.

But i really don't want to stop this project, i have planned to make it as an free opensource  game like supertuxkart.

My aim is to have an high-quality game with a lot of game-functions
in the first phase i set up some graphics.

i also don't have a website now, that comes a bit later.

You play the blender-monkey suzanne (the model isn't the best, it is only a placeholder at the moment)
and you have to resque/save bigbuckbunny

it is a bit buggy at the moment, i added an debug mode, where you can fly (f1).
sometimes the player hangs when jumping, when this happens, go into debugmode and then out of it (press f1 two times)

here i have some screenshots: