90517
OOH! OOH! I KNOW THIS ONE! I KNOW THIS ONE! UHH... UHH... I WANNA BE THE GUY!!! It's notorious for beyond lunatic difficulty. Most people can't even figure out how to get past the first screen without a walkthrough. It's that hard. Basic gameplay basically boils down to that of your average 2-D platformer; jumping, double jumping, wall jumping, the usual.