Kaizo Mario World
From SMWiki
Super Mario World: Kaizo Edition (or Kaizo Mario World, for short) is a very difficult Japanese romhack of Super Mario World. The hack became very popular, and ended up spawning "Kaizo hacks", ROM hacks that feature many variations on the ideas of Kaizo World as well as some original ideas.
This hack features about 95% of things that SMW Central don't accept in their hack, such as: Floating munchers, stacked munchers, unfair level design, death after goal point, unfair invisible coinblock placement, bad level timer (very low time in for example, special level 2) and others. In fact, SMWC's hack standards were made as a direct response to Kaizo hacks.
The youtube posting of the original creator’s videos states:
[Asshole Mario] is not the real name for this series of videos, but it is my personal name for it. The literal translated name for 自作の改造マリオ(スーパーマリオワールド)を友人にプレイさせる is “Making my friend play through my own Mario(Super Mario World) hack”, hence Kaizo(hack) Mario to the USA.

