Play as Samus without her suit
Complete the first quest without dying and with all the items ice beam as your gun weapon Press Start after the credits have completed If you have completed the game correctly Samus will take off her suit in the ending You will start with all your items you gained in the previous quest minus your missiles and suit in the next game
Refill energy easily
Go to a pipe that has enemies constantly appearing at ground level with no other enemies around Just keep shooting and the enemies will fly into your bullets leaving energy and other items