Time Keeper 4792 or some year number that sounds cool (mostly so a google search would find something other than a bunch of time management apps) is an RPG concept that implements time travel.  The basic premise is that our hero finds out, on new years eve, that he is the time keeper and his job is to fix the previous year.  Armed with a newspaper that dynamically shows the end result of any action the player takes you set out to make the perfect year.  No small task indeed with tons of alternate "winning" endings including "Lord of the Flies" where all the adults are killed and the kids take over, "Vigilante Kid" kill someones parents and maybe he becomes a dark knight, and "some people just want to see the world burn" which should be self explanatory. 

To make this game I could not employ a standard RPG engine and had to design my own engine and tile manager.  This concept requires a very complex system to keep the NPCs moving along like clockwork and react in specific ways so any given action will have a very definite and calculable outcome.  I've spent the bulk of my development time working on fun tile management strategies so placing roads, tracks, roofs, and water borders is automatic.  You just define the tiles (see tile picker below) and the system chooses the right tile to place based on the tiles around it.  The rest of my time was developing the time system, months/days/hours etc and the day night function.  

Time Keeper 3119