Make sure both your SRB2 and Mario Bros are properly updated to the latest version. If you're on Android, that version is unofficial and may have issues.
Wall jumps have always been lesser for a single wall, you're not supposed to be able to just wall jump up one wall. I honestly forgot about the ramp jump change, and I think I'll probably end up reverting it eventually. Also, for your lagging and crashing, are you using the Android version? If you are, it's unsupported and unstable, so make sure you're using an official version.