I'm actually from a Super Monkey Ball 2 hacking community which, among other things, has been working on a Ghidra decompilation for a bit over a year now. We collaborate on a shared Ghidra server and have tons of stuff labelled and annotated at this point!
We also have the ability to inject C++ directly into the game for modding. I'm also the author of ApeSphere, a practice mod for SMB2 with features like savestates: https://github.com/complexplane/apesphere . Take a look at rel/savestate.cpp for a taste of what we can do.
As an example, here's a full decompilation of the camera code which runs after the ball passes through the goal: https://cdn.discordapp.com/attachments/463221047471374337/79...
We also have the ability to inject C++ directly into the game for modding. I'm also the author of ApeSphere, a practice mod for SMB2 with features like savestates: https://github.com/complexplane/apesphere . Take a look at rel/savestate.cpp for a taste of what we can do.