I'm currently working on an update to a game that's currently on the App Store that supports both iPhone and iPad. There is a single player mode and multiplayer mode. The multiplayer mode is run through Game Center. The single player mode is just local to the device. The single player mode data is not synced to a server. We've had a few requests from people who have both an iPhone and an iPad to sync single player data so they can play on the iPhone and pickup where they left off on the iPad. We've managed to punt on this syncing because syncing is hard.
But now... now we want to implement single player leaderboards. So without syncing single player data, we could run into this scenario:
- A player starts playing on their iPhone and racks up an impressive score on the leaderboard, linked to her Game Center ID.
- Later, that same player with her same Game Center ID picks up her iPad and starts playing the game for the first time. The iPad knows nothing about her impressive games she previously played on her iPhone. So it submits a less impressive leaderboard score.
- A player is sad
Before I plop down and build in syncing, I'd like to hear how other people have dealt with this problem.
Game Centre will only ever show the highest score. It won't override a higher score if you submit a lower score unless you set it up to do that. These settings are in iTunes Connect when you add leaderboards.