How the hell do you get out of Hollow Bastion in Kingdom Hearts 1?!?

okay, well, we entered Hollow Bastion and we didn't defeat Riku yet, we kept dying. We went to EVERY SAVE POINT we could find, (waterway, and in the rocks and platforms or whatever) and it doesn't let us board the ffing gummi ship. Do you have to beat the world before you can leave?! That's frigging cruel... yeah but uh.. please dear god respond asap. Thankks.