If it is like the Ds version it is simple. Obtain all the stars or there is a way to get the cannon without all the stars. By the cannon there should be trees. This can be hard to do. Run to the tree on the left jump and dive. If done correctly you should be halfway undergroun then drop from the tree and you will be underground. Swim over underneath the cannon and jump in. (P.S. This trick only works if the moat is full.
Collect all 120 stars and go to the cannon outside. If you are playing super Mario 64 ds get all 150 stars and go to the cannon outside.
Get all 150 stars
either use a cannon or a wing cap
Waluigi is not in the game at all.
You cannon play multiplayer mini games in Super Mario 64 DS. Are you sure you don't mean New Super Mario Brothers? It has multiplayer mini games.
You can use the cannon to shoot up to the top of the castle. Yoshi is there in the Nintendo 64 version. After you talk to him, you will have 100 lives.
All 120.
Collect 120 stars
You gotta get all of the stars, then the cannon outside will open up.
get all of the stars and then jump in the cannon near the lake.
You use the moon jump cheat.
not