On most stages, mainly the early stages, do the following:
When you begin, simply fly to 9999 km high, staying on the left boundry of the level, right where you began. When you get to the top, there is a stream of regenerating bells of most colors!

After the credits, depending on how many Fairies, Doors and Goals you collected you'll get a percentage score. The percentage score dictates what rank you get and depending on the rank, you'll get one of the following endings:

Pause the game, press A 5 times, B 5 times, X 5 times, Y 5 times, L 5 times, R 5 times and unpause. Now, hold Start to pause the game and while holding, press the directional keys to move anywhere on the stage map. If you wish, press R to remove the map from the screen.