Needs a lot of work. There are certain positions that are unable to reach (i tried to perform a PLL and i was unable to position the cube as i use to when i start the algorithm), the timer shouldn't start after the scramble if one isn't even given time to inspect the cube, it would be good also to have a moves counter. Oh, and i guess it would be a good idea to use the "classic" colors on the cube, or at least leave it as an option.
There are several other rubik's cube simulators out there, maybe adding something 'new' can make this one stand apart from the rest. Good work though, keep it up.