New Metroid was on-rails shooter
Metroid: Other M wasn't always meant to be a hybrid side-scrolling 3D action game - the original concept detailed an on-rails shooter.
Speaking at GDC, producer Yoshio Sakamoto described how the upcoming Metroid game was pitched as a shooter with "invisible walls." In other words, you'd explore levels with a limited range of motion: an on-rails shooter.
Of course, that plan changed and Metroid: Other M now possesses a unique structure that has you explore levels with the Wii Remote held sideways and then flip it forward to combat enemies in the first-person perspective.
Also changed: female protagonist Samus Aran's hair colour. Initially a brunette, Team Ninja bleached it blond. Metroid: Other M will be available for Wii this summer.