Most Wii games come on a regular 4.7 GB DVD. There are a few exceptions, however, like Super Smash Bros. Brawl and Metroid Prime Trilogy. In the case of those games, dual-layered DVDs were required due to the amount of content in them.
You can add Metroid: Other M to that list as well. Due to the sheer amount of content — largely due to the game’s cutscenes — Other M comes on a dual-layered disc. In a second Iwata Asks segment, this time with members of Team Ninja, we discover that even while using a dual-layered DVD, the development team barely managed to squeeze all the content in.
Team Ninja tell Iwata that they were literally shaving mere seconds off movies in places in order to be able to squeeze the game’s data onto the disc without any noticeable visual inconsistencies during the cutscenes.