Troy - Letters & Numbers Train

My son played this game a couple times and loved it, and now it won't load. The app opens and shows the loading screen and then closes. The other 2 apps in this bundle work fine. My iPad has iOS 9. I tried closing and re-downloading the app to the home screen, and restarting the iPad. Help!

I would have given the app 5 stars , but because the app doesn’t say the letter or number I feel as if it’s not a great app. If it says and sound out the letter my child I feel would learn faster