The idea itself is not too bad. Well maybe it is , but there is some coherence to it. It really sounds to me like this guy wants to make a game like the movie Cube. Cube is somewhat of a horror movie , where a couple of people are stuck in a cube , not in the same one , but meet throught the movie , each one is in a cube of their own to start. Each cube is a room , with doors on each side , the people in the cubes have no idea where they are or how they got there , and are trying to figure that out as well as a way to get out , the thing is , some of the cubes have deadly traps that will kill you (like the grid that slices you to small cubes , something resident evil movie copied from them) , so eventually people run into each other , and figure out about the traps , and start trying to decipher which rooms have them , and they run into some strange markings on the doors , and one of the people in the group through some mathematical formula is able to figure out which cubes have traps. It's a very good movie , specially part 1 and 2 , didnt care much for Cube 3 which was called Cube Zero. So essentially in the movie , the people are in 1 big cube made of many small cubes which are rooms which is where the people are , and the puzzle is finding the way out, btw , at some point in the movie they figure out the cube moves kinda like a rubix cube , making it more difficult to find the exit. I think from this idea , a cube game would definately be possible specially if made in the sense of a horror game rather than an mmorpg. Though I m not sure the whole MMORPG thing would work , it is possible , maybe if more cubes where involved , i.e. different cubes of cubes that somehow interlink , but then you need a good way of taking this concept into a playable and fun mmorpg game.

Edit: Btw , here's a link to a trailer: http://www.imdb.com/title/tt0123755/trailers