You can make use of dispatch_after if you want to achieve something similar to NSTimer and block execution.
Here is the sample code for the same:
int64_t delayInSeconds = gameInterval; // Your Game Interval as mentioned above by you
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
// Update your label here.
});
Hope this helps.