Rotated ground in BGE

[Cotaks (- Click for (UP)Bge resources)]

indeed default gravity is 9.8 so you can simply add a force to the player/thing to counter it.
search the resource section there are a few examples.

or is something like this you are looking for?

Walk and stick on animated objects and planets

New and last version v3 walk on animated object walk on beveled cubes walk on spheres jump at all sides Well a video explains more [Blender game engine, stick to it and walk animated objects] Ideal for elevators/platforms/animated objects/ etc. etc. If you want to walk around, here is the .blend walk around and stick to animated objects.blend (583.8 KB)