There are many serious bugs in Game Center for iOS7. None of the deficiencies of GC on iOS6 were addressed, and new crashes, hangs, and other bugs were added. It's as if Apple couldn't care less that games are the single biggest category of apps selling all those iPads and other iOS devices. But for this post, I will focus on one issue in particular.
Game Center reports inconsistent achievements across my many iOS + Mac devices. When I win an achievement once, I expect and demand that GC actually credit me for it permanently. In many instances, the achievement shows in GC on the device where I won the achievement, but it does not show on GC on any other device or computer. Note that I'm NOT talking about viewing achievements within a given application, I'm just talking about GC itself. This is NOT a problem of an individual game, it is a problem with the GC architecture. When I see a GC notification pop up that I've won an achievement, I expect that achievement to actually show in GC, both on the current device, and on every other device.
This is not a problem with replication lag. I've tried waiting for days to see achievements appear across devices -- they don't. I've tried force quitting GC and every game on the system, then re-launching GC, only to see exactly what I saw before -- different scores on different devices.
There are even inconsistencies on a single device. Different screens within GC show different scores. Some of these problems resolve themselves over time, as if different parts of the GC app rely on different caches, and those caches refresh on different schedules. I can forgive some replication lag, provided everything eventually replicates everywhere. But sometimes, the discrepancies never go away, and GC permanently reports results that don't make sense. Looking on the achievements page for a single game, I often a set of achievements and a total achievement score which just plain don't match, days after having won the achievements in question.
This is also not caused by offline achievements. GC is so abysmally poor at handling offline achievements that it deserves its own post, and I won't go into the details further here, other than to say that I no longer play GC games while offline. My device of choice is a wifi iPad (the last model with the large cable connector, updated to run iOS 7.0.2), and I always make sure I'm connected to wifi before playing any GC games. And by making sure I'm connected to wifi, I mean positively confirming that I can reach the web and check email before launching my game. Despite ensuring that I'm always online when I play, achievements still do not replicate.
This is also not caused by game bugs. Apple made a terrible design decision to not treat achievements like gold -- or even to treat them as important as email. Email is never lost. Achievements are frequently dropped. A game should not need to be implemented to re-register achievements, even if they were won offline. In any case, the point is, this bug has nothing to do with any individual game. I can fire up multiple iOS + Mac devices and see different scores within the GC apps.
My question is, how do I fix this? I can find no way to force game center to resync with the master achievements database in the cloud. I can't even find a way to send feedback directly to the GC team, or open a support topic directly about GC. (I would be extremely surprised if Garage Band were more popular than Game Center. Yet Garage Band has a dedicated support section, whereas the word "game" doesn't even appear anywhere on Apple's support communities topic list.)
Thanks in advance for your help.