GREAT IDEA! I would like to give my contribution.
Original defrag tended to chain clusters from big files, it would be nice to add a color code like Norton Disk Doctor's to locate big file chunks to be able to arrange them and get some "points" maybe? and have some sort of Final score and a Leaderboard?
Original program cannot handle unmovable system/hidden files. Along with the total files occupation it would be nice to have them selectable in the options just like the bad sectors are.
A time attack mode?
Keep up the good work! I Love the case chime!