All levels and FMV sequences:
At the main menu, choose the "Play Game" selection. Choose the slot you wish to play, then press Black, White, Black, White, X on the next screen to unlock all levels and FMV sequences.

Bonus Boss battle:
Wait until the credits end to face another Boss in a bonus battle.

Cheat Menu:
Pause the game, then use the D-pad to enter Up, Up, Down, Down, Left, Right, Left, Right, White, Black, X. This must be done again to enable multiple cheats at once.

Defeating Ethan:
When facing Ethan in the bonus battle (if you took Oliva), he will start charging the black ball above his head. Equip the Surge power. When he tosses it, you can knock it back. He will catch it and throw it back three more times. After the third time, it will hit him. He will then fall to the ground and three gold colored rocks will fall from the ceiling. Use Lift to pick them up and throw them. Repeat this about four or five times to kill him. You and Ethan will then get sucked into a warp hole and get dumped in a snowstorm. Your health will drop very quickly. Walk to the top left and a strange figure will find you.

Escape pod choice:
After you return to the escape pod bay with Olivia, Ethan tells you to take Olivia and run to the escape pod while Olivia tells you to take Ethan. At this point, you may choose either one depending on who you walk towards. If you walk towards Ethan, you take him to the pod and see Olivia get scanned. If you walk towards Olivia, you take her to the pod and see Ethan get scanned. Additionally, at the end of the first chapter, you will choose who gets to come with you on the escape pod. This choice only affects the banter between your character and the one you save. After the credits end, you will play the epilogue, and the person you left behind in the first chapter is who becomes the final Boss in the game.