Takemoto, an unknown Japanese rom hacker. It was made to split your eyes out and make you cry. The game includes difficult, precision jumps; multiple obstacles at once; and many, many nasty traps along the way. Kaizo Mario is reliant on skill, patience, and sanity. If you aren't dying every fifteen seconds you are probably cheating.
Imagine loading up Super Mario World and entering the first level. Instead of the comfort of flat ground and the odd Koopa, there's a large gap with Boo ghosts fading in and out of existence. Jumping into the void, you see a pipe in the distance. It's a beacon of salvation but, to get there, you must utilise Mario's spin jump to bounce from Boo to disappearing Boo; relying on timing and precision.