I think I know what needs to be fixed in the API.
According to the iOS GC documentation, there are 4 possible values for the GameCenter Controller View State.
(Default, Leaderboards, Achievements, Challenges)
typedef enum /*: NSInteger */ {
GKGameCenterViewControllerState Default = -1,
GKGameCenterViewControllerState Leaderboards ,
GKGameCenterViewControllerState Achievements ,
GKGameCenterViewControllerState Challenges ,
} GKGameCenterViewControllerState;
http://developer.apple.com/library/ios/#documentation/GameKit/Reference/GKGameCenterViewController_Ref/Reference/Reference.html#//apple_ref/occ/cl/GKGameCenterViewController
Corona API does not support the Default state. “leaderboards”, “achievements”, “friendRequest” are the only ones supported.
It needs " default".