The Wii's regular DVDs can fit a fair bit of content, but with so many cutscenes and assets, Metroid Other M will be taking up a double sided disc.
In the second Iwata asks feature (via Siliconera), the team reveals that even with twice as much space to play with, it was tricky fitting everything in. Movies had to be trimmed ever-so-slightly, with mere seconds removed to achieved a balanced visual experience throughout - without the need to compress certain sections.
Samus’s Gravity Suit, seen in most games since Super Metroid on the SNES, won’t make a direct appearance in Other M, instead will be shown as a purple glow to indicate the upgraded ability is in effect. Reason being Yoshio Sakamoto felt that, with it’s purple guise, the suit looked out of place towards the end stages of the game. Same abilities, slightly different look.

Just over a week now folks!