First, confirm that you have updated to the latest version of CSR Classics, as our most recent update makes the game run smoothly for most players.
If this doesn't work, please reset your device by switching it off then back on. Once the device has been turned back on, try loading CSR Classics, and confirm whether you are still experiencing slowdown or lag.
If you are still having problems after following the steps above, please try out the following troubleshooting steps listed in the links below:
How do I force close the game on Android?
How do I force close the game on iOS?
How do I force close the game on Android?
How do I force close the game on iOS?