Super Mario 64/Bowser in the Sky

To get into this stage, a player requires 70 stars and needs to have beaten Bowser in the Fire Sea.

Reaching Bowser
When you enter Bowser in the Sky, there will be no message. Do a triple jump on to the first three platforms and jump onto the sliding blue rock. Afterwards, run quickly across the tilting pathway, and run up the slant. Kill the Goombas and leap onto the spinner. There’s a life inside the box. Jump onto the next spinner, and then the gray platform. Watch out for the piranha flower. Continue on the wooden plank and jump onto the rotating platform. Jump up and go right. Pound the “!” switch to activate the stairs. Run up the slope, but watch out for fire blasters. Run across and down to the checkered platform with the piranha flower and hop onto the moving platform and jump over the obstacles. Next, hop onto the ground and to the spinners and up the pole. Be careful of the spinners. To jump of, make sure Mario is facing away from the Goombas. Run on the sliding platforms and onto the pole; making sure Mario us facing away from the next platform. Dodge the bob-ombs and fire ball. Jump from the first rotating platform to the second and onto the gray space. Watch out for the strong winds. There’s a 1-up by the far left pillar. Good Luck!

Red Coin Route

 * 1) Above third gray slab, *use the box.
 * 2) In the corner by the piranha flower.
 * 3) On the ledge below the first set of rotating platforms.
 * 4) At the top of the slope with the fire blasters.
 * 5) On top of one of the blocks above the spinning platform.
 * 6) On the of the spinning platform with the fireball.
 * 7) On the top of the pole in the middle of the moving platforms.
 * 8) On a ledge beneath the stairs to the entrance to fight Bowser.

Defeating Bowser
Get behind Bowser and grab his tail. Spin him slowly around by rotating the analog stick 360 degrees. Then toss him a little way and run up behind him and grab him again. Repeat throwing Bowser until you get close to a mine, and let him have it. The rings he stomps out are easy to jump over the closer you stand to Bowser. After you throw him into a spike twice, Bowser will break the platform into a star. Stand in the middle when he is doing this.

Upon defeating Bowser the third time, you will have beaten the game. However, you will still have a chance to go back and continue acquiring all the stars.

PS: When you defeat him, he gives you a star with the same effect as a wing cap/feather. This leads to the fact that there are actually 121/151 stars in the game.