The third major N64 game is a fun trip. It's got issues, sure, but it manages to succeed as a game on the strength of the flight levels and a bit of charm. This is a side-story that takes place between Empire Strikes Back and Return of the Jedi.
The under-sea lair of Treasure Knight looks pretty rad. It reminds me of that underwater reactor place in Final Fantasy VII. Or maybe it was VIII...it had archways and stuff.