Poyo, an addictive arcade puzzler. It's quite hard at first as it requires a lot of precise jumping, but if you're into such old school stuff, you'll enjoy it. I'm done with the first world.
Also
Rolling Madness 3D, a 3D remake of Marble Madness. Even harder than Poyo due to its amazingly short time limit. Level 4 is my cap at the moment.
Both are free so check them out.