Perform a backup (to iTunes or iCloud). Factory reset your phone (General > Reset > Reset All)**. Restore from backup. Worked with my 5s. **at your own risk
I've found a (slightly drastic) workaround. Backup your device. Carey out a factory reset. Restore your data. Game then runs okay. Do this ONLY if you are familiar with backup/reset/restore process, and at your own risk.....
I've found a resolution to the issue, but only use it if you are au fait with what is involved, AND use it at your own peril.... Carry out a backup of your device, then a full reset, then restore from your backup. My reset didn't go to plan as the iPhone 5S got its knickers in a twist and I had to restore via iTunes…
Still no luck. In Service Delivery Management, such a Denial of Service is a major Problem and I would expect all resources to be thrown into a resolution. Additionally, I would expect updates to customers at least every 2 hours. Yes, I was a SDM for a well-known Japanese computer manufacturer that sounds like Ju-jitsu....