Mobile apps that crash frustrate and disengage users. Will it be Android or iOS users the ones who are going to leave your app first?
iOS user are the most demanding users. Used to the streamlined experience of iOS, iOS users won't tolerate many crashes, especially when it comes to games!
The only way to ensure that your app will continue to perform as intended, is by monitoring any errors that may occur, analyzing their frequency and the circumstances under which they occur (in order to be able to prioritize and troubleshoot), and finally resolving them and letting your users know.