Play as girl with bonus weapons:
Enter JUSTIN BAILEY ------ ------ as a password to play as the girl and start at Ridley's Lair.

Alternate game:
Enter 999999 999999 KKKKKK KKKKKK as a password with no Varia suit and a different ending.

Super jump:
Hold Right on controller two and press A on controller one.

Quit game play:
Press Start to pause game play. Hold Up + A on controller two to display the current password.

Hint: 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.

Hint: 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.

Status	Password
Slightly powered in Brinstar	007ltp W20000 025kHa 8A00?Y
Ridley	00U--- -u0000 0AFw9Y 1800sb
Ready for Kraid	0Gz--- -m3e0G 00VvjS 3m00n?
Tourian	M7---- --zOA0 2T-tfm a000d5 atop
In suit, end game	uVt-Fg boo-W7 9t?lM0 O00Gsi
No suit, end game, best ending	X----- --N?WO dV-Gm9 W01GMI
Play as the girl with all the arsenal weapons	mMuiS1 II6-GE Jls?h0 m00WRM
Weird Code; Freeze, Varia, No bombs, odd ending	Daniel Daniel Daniel Daniel
Brinstar with 10 missiles, 1 Energy Tank,and Long Wave Beam	018000 020000 04GA00 0000Xg
215 missiles, 5 Energy Tanks, all power-ups, both mini-Bosses defeated	X-z-uJ lls0W0
Second quest	022400 A00000 05?00m 0000aS
Second quest as Samus without suit	0WX002 W00004 1VW0C0 0000MO