I love the game Spelunky! It’s a 2D platformer famous for its difficulty. The art, the music, the controls, the gameplay is just splendid and I wondered often in what direction the game could take, would it transcend into 3D space. The only thing that popped into my mind was Mario Galaxy. I think the style would do Spelunky well, but gameplay wise I am still not sure if it would work in 3D. But Mario did the jump from 2D to 3D, so why not Spelunky!
However, I dont think this spherical map style would work for a normal Spelunky level, but it could be a sort of hub world, like in Mario Galaxy, that connects to other levels that has a more normal camera & conventional leveldesign used in Mario 64 etc. Great fun image to work on!