"Some tidbits on the development of Super Mario Sunshine; the first two are fairly new, the other ones are older, but still not widely known:
- An unused camera behaviour in the game's code suggests that the developers at least experimented with a multiplayer mode. Although it was dropped for unknown reasons, the early beta multiplayer camera is still functional.
-Work on Sunshine began around Late 2000/Early 2001, so that the game was in development for only around one and a half years. It heavily suffered from time constraints, which even Miyamoto admitted 2003 in an interview.
-At least five worlds were cut from the final game. Their names can still be found in the game's code.
- Sunshine originally run at 60 fps, even the version shown at E3 2002 mere weeks before release was 60 fps. The final game was downgraded to 30 fps for unknown reasons."
I left out some tidbits, but they can be found in the article. Anyway, I don't even want to imagine how crazy multiplayer in Sunshine would have been! Also, I'm not too surprised that Sunshine suffered from time constraints. It's not a bad game, but it did feel very rushed and that's why it became the black sheep of the Mario franchise. There's no doubt that a Sunshine sequel most likely wouldn't suffer from such problems.
---Member of the official Squeezol Fanclub---