When I play on my iPad it crashes after a short while

When I play on my iPad it crashes after a short while. It can be when I play by myself or playing over a server. I can host and it crashes or my son can host and it still crashes.
Please help!
I have closed the program by swiping up.
I have turned off and re started.
I have ctl, alt, del, (hard shut down).
I have deleted the game, lost some awesome work, and re-loaded.
Deleted heaps of photos to make room.

Does the game need a certain amount of free space to work properly?

Please help.