It can work someplaces. Mostly cartoony stuff with lots of inertia like Sonic games etc. You picked a wrong example with castlevania because I finished POR on DS and loved it to bits BUT the freakin' walk-cycles. They're so bad. Not only do they glide, not only they're oversmoothed, not only are the actual runs extremely artifical and silly, they're also SEMI-SIDEWAYS. On a fully side-ways, no perspective platformer. They're humanoid, and look very bad.