Syobon Action, sometimes called Cat Mario, Shobon Action or Action Shobon, is a freeware game from Japan. The first complete version was released on the game's official website.
Later, an open source version of the game was released which lead to not only the Windows version but also ports for AmigaOS 4.1 and Linux. The official version from the website is only at 10mb.
The gameplay is very similar to any of the famous sidescrolling games in the Super Mario-series. However, the game is filled with different hidden traps and fakes that makes the game a lot more difficult than any Super Mario game, especially to players used to Super Mario. For example, eating a red mushroom, which makes you big and strong in Super Mario, makes you become so big that you fall through the map and die in Syobon Action.
To balance up this extremely difficult gameplay, you have an infinite amount of lives. You start at 3x, but once you drop down below 0, the life counter goes negative. Thus, one can argue that a goal of the game could be to complete it with as few deaths as possible, and a -500 in life count could thus be a rather bad run.
The first level of the game is based on the first level of Super Mario, with the pipes and the flag at the finish line, whilst the second level is based on the underground levels you can reach through earlier mentioned pipes. However, the way of completing the levels is very different from the Super Mario games. Simply trying to jump across the flag in the first level will kill you every time, and you are forced to think in new ways. This especially applies at the end of the second level, where you have to take your thinking beyond the rational in order to complete the level and do what seems not to be supposed to be done. For this reason, many people use video guides in order to complete the game, since the process of actually completing it is already frustrating enough, and finding all the dangers and the right way is far, far worse.