Cluedo is, of course, a game of deduction: there has been a murder, and the players must determine which of them is the murderer, what weapon was used, and where the crime took place. To do this, they walk from room to room, making 'suggestions' as to whodunnit and whatdunnit (with 'wheredunnit' being limited to the room they happen to be in). Each player has a hand of cards, and must use these to disprove the suggestion - if they can.

PPC Cluedo is all of the above, only more so. With what Christianne Shieh described as 'seventeen suspects, and far too many locations and murder weapons to count', it would quite likely be unplayable but for a few changes to the rules:

1/ Rather than the two secret passages on the original board, there are four (described as 'portals', but operating the same way). This encourages greater mobility, but not as much as...
2/ Movement is through the roll of one die. However, on a roll of 1, the player fails to adequately distract themselves, and thus ends up somewhere entirely other than their intended destination. Specifically, they are transported to a random room on the map. Their turn then continues as normal (suggestions or accusations).
3/ As in standard Cluedo, suggesting a particular scenario immediately moves the suspect and weapon to the room you are in. For web-based play (which may happen), the sheer number of players means it is necessary to treat all turns as simultaneous - that is, everyone moves and suggests as if they were the first player, without having to worry about being relocated by another player's suggestion. Relocation itself is performed after the suggestions are concluded, and runs clockwise from top left - thus it is possible for a given player to be moved several times before settling down.

The PPC Cluedo Board
Linked from the PPC Wiki to allow a full-sized version. Note that it is sized so as to just fit on a standard floppy disk; this may be coincidence.

The Cards
58 playing cards, plus a somewhat shrunken version of the board.