The game centers around trying to determine which of the characters is guilty of a murder. The game is subtitled a "youdunit" because every character, during creation, is assumed to be the guilty party. A character's backstory must include enough incriminating and contradictory data to "prove" they are guilty of the murder - if the information can be discovered by other characters during play. The game proceeds in scenes with players taking turns as the primary narrator for a scene.
Characters have three Attributes: Brains, Beauty, and Braun [sic]. These have a "Stat" or numeric rating. Characters also have various other Traits that allow them to investigate and find out about other character's secrets. Action resolution uses a dice pool that yields a success count.
Note the game author/submitter was known only as "secret" on the forums. The game was entered as an text file.