Games keep crashing on my iPhone

1) Double check to ensure that you have ample free storage space available on your iPhone. Open Settings ➡️ General ➡️ About ➡️ Available: Here you will see the available storage space on your iPhone. You should maintain at least 15GB or more free storage space for the iPhone’s efficient operation.

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2) You may have a poor battery condition which cannot provide sufficient power for peak performance. What is the Battery Health of your iPhone? Open Settings ➡️ Battery ➡️ Battery Health and let us know which percentage you see for Maximum Capacity. Also note what is written under Peak Performance. If your battery's Maximum Capacity shows a value of 80% or less, then it has gone through its lifecycle and therefore should be replaced, according to Apple.

Axel F.

If an app isn't responding, you can quit it and then reopen it to try and resolve the issue. (Typically, there's no reason to quit an app; quitting it doesn't save battery power, for example.) To quit the app, open the App Switcher, swipe right to find the app, then swipe up on the app.

Quit and reopen an app on iPhone - Apple Support (IN)