I wanna be the Guy: Gaiden is a BRUTAL platformer. It's the sequel to I wanna be the Guy. Both games are as hard as heck.
Download Link:
http://gamejolt.com/games/action/i-wanna-be-the-guy-gaiden/8598/Play this if for some reason you wanna rage. I'm serious.
IWBTG: Gaiden is extremely buggy for some reason. IN EVERY COMPUTER. I'm not joking. I'm gonna update my signature to show you the specs I have, they are fairly high, but the game just KEEPS BEING BUGGY.