Telport pad to the start sounds a bit harsh. How about having some suspended 4x4 plates all held equal distances apart, but most break about 0.5 seconds after getting on them, promoting fast jumping and quick reflexes - not all spots where there should be one there is one, meaning people have to constantly see where they have to jump next. Also, how about a sort of 'puzzle', a player has to stop a pinball from going into a little hole (by standing infront of it) else they are killed.