I had the problem of game crashing but the app ( heroes charge) take to many memory. Try this and see if it helps.1st Have extra usage space ,usually around 1gb or higher.
2nd restart you device ,by turning off and turning back again..3rd close your other apps ,including safari ( web pages, windows...etc).
And if your have a iPhone jail break or.rooted for smartphone make sure you get a cleaner ( icleaner ). This work for me ,wash rinse repeat.you get a day or more playtime ,until the memory leak is fix ,by the dev.