Even though there's been more worlds added recently, they also added ads without a way to pay to remove them. So you'll have to play offline, on emulator, or get a mobile adblock. (Something like NetGuard should work fine.)

Also if anyone finds the version before they added ads I may allow that to be run on. (And I'd appreciate knowing what version that's called.)

I use "3C toolbox". Requires root, but you can disable any component ("activity", "provider", "receiver" or "service") of any app, so it's like a more customisable version of adblock. For this one, it's pretty easy: Disable everything except "com.raongames.bounceball.BounceBallActivity". I've also disabled all permissions except for "prevent phone from sleeping", but that probably isn't needed either if you're speedrunning. ;) You might also need to delete some cached ads ("manage"→"open"→"data folder" in 3C), but I don't know which folder they're in. I just deleted everything, because I had freshly installed the app anyway. Note that disabling internet permissions will also prevent all online features, of course. I didn't test whether it's sufficient to just disable the components instead.