I think that there should be a 'replaying' or 'replayed' option to games. I often like to play through games again and it would be nice to have this option.
I am also confused about the difference between 'completed' and 'mastered', and I wonder if both are really needed.
I was kind of looking to be able to mark things with Completed or Mastered and at the same time with Want to Play so I have a list of games that I beat but I enjoy replaying from time to time.
Thanks for the feedback! I do intend to make it more explicit that a game is being "replayed" probably by adding a play count and sub-status/property where you can say "I'm on the 5th playthrough of this game" kind of thing. That's planned!
As far as confusion between Completed and Mastered--this isn't explained enough, I agree. The intention is that Completed is 100% completed games. Mastered is like, 100% + All Achievements + I'm a boss at this game kind of thing. It can also just be a personal feeling. someone might be tournament-level for a game, they've Mastered it.
I do intend to make that more distinct and provide guidance for people. One thing that both have though is a fun little celebration anytime a game is added to them because they are both important milestones!