The Game-in-a-Week version of Nicholas Spratt (the downloadable one available from the sidebar) had a reasonably simple murder timeline generation system.  Basically, it picked a murderer and someone to be murdered, and picked a time during the day when the murder would be committed, then “locked” the room in that moment so that no other characters could blunder in and disturb the action.  It then picked an earlier time for the murderer to be alone in the room with the murder weapon, and locked the room so that no one else could be in the study at that time, either.  And then it used a pseudo-random system to have the remaining characters wander about between the game’s 24 turns, and recorded what everyone saw, and who was in the room with them.  (There was also a 2% chance of a mistaken memory, where a particular guest wouldn’t notice someone or would remember the wrong person, etc)

And that’s basically all there was to it.

For Spratt 2.0, I’m thinking about dramatically expanding on this.  Here’s the list of changes I want to make:

• Give all guests a randomly selected motive for wanting to murder the victim.  This is just for flavour. :)
• Randomise the mansion floorplan.  At least one room per guest (including the victim).
• Add doors to the mansion, to show how to move from room to room and from room to hallway.  Doors may be open or closed.
• Add multiple possible murder weapons.  Probably one murder weapon per mansion room
• Change the murder timeline from using 15-minute timeslices to 5-second timeslices, for finer grained accuracy on guest vs guest visibility.  Guest memories remain labelled according to 15-minute timeslices, but multiple things can now happen within a single timeslice.  Guests may move only a single grid space per five second timeslice.  Two or more guests may occupy the same grid space as long as all or all but one are still walking.
• When guests are in a hallway, they can see any other guest within line of sight, including those on the other sides of open doors.
• Add collision to the mansion walls, and let the player walk around inside the mansion.  one guest will be in each room, either stationary or pacing.  Talking to a living guest will let you examine their memories as in the GiaW version.  “Talking” to the dead guest will provide details about how he died (gunshot wound, bruising, etc, to help the player determine the murder weapon).
• Grandfather clock in the entrance hall, so those in the entrance hall will know the exact time, while others only know the last 15 minute bell that has chimed.  This is probably just flavour;  probably won’t matter to actually solving the mystery.
• Have two or more guests planning to perform the murder, and gather/return murder weapons, instead of only one guest doing this.
• Consider witnesses during the murder generation phase, and actually make sure that there are witnesses present to see particular key moments.  (Someone’s opportunity to get a murder weapon, etc.)