101% of Items Collected:
In GMFC Compound, you're supposed to see a cinema and then blast a yellow crate to get the Missile Launcher. Now, right before the "trigger wall" leading to activate the cinema, there is a boot-shaped formation. Jump on it and you will be launched onto the ledge above, letting you to skip the activation of the cinema and go straight to the Missile Launcher. Grab it and activate the cinema, you will see that the yellow crate reappears, with another Missile Launcher. Get this one and the other 99 items and you will have 101% completion.

Kill Metroids with Ease:
All you need is the power beam and a door. Shoot the metroid with the beam, to aggrivate it onto you. Face the metroid, with your back to the door and wait. Lock onto the metroid and when it charges you, perform a side-dodge. If the metroid hits the door or somewhere near it, it will explode.

Sketch gallery:
Beat the game on Normal.

Hard mode:
Beat the game.

Storyboard gallery:
Beat the game on Hard.

Special thanks to Revolution readers *Doug*, Andy Miller, Tycho, A-Unit, and aranus!