I know this is an old iOS, but I for one am still using it on iPhone 5C and im sure a chunk of users still are too. I will be getting a new iPhone soon with iOS10 for testing ect, but its just something that I noticed that support might need to know about and look into and perhaps fix. Because there is still X% of iPhone users still on this iOS, even if its not the majority. Even GLTCH, 99 Moons ect all crash after the "start" screen is done loading.
It is rather the device than the OS I believe. I am on 8.4 with my test device and it's the same. Some work some others don't. Mostly because of memory issues of the device which in this case is 4s. GLTCH does work though. That's strange.
There is indeed a specific crash on very early iOS 8 versions. This is on the list to fix... but realistically your talking about a very small fraction of a percent of total iOS 8 users (iOS 8 is only like 5%-10% of market total). The majority of users using iOS 8 will be on iOS 8.4.