Metroid: Other M isn’t on-rails, but it does have elements from the genre
This is starting to get confusing! First we heard that, at one point, there was a possibility that Metroid: Other M would be on-rails. But then we heard that Sakamoto was misinterpreted. Now, Sakamoto says that while the game isn’t on-rails, it does have some elements from the genre. Perhaps you’ll get a better understanding of the situation after you read the quote below…
“It’s impossible to say that there aren’t any remnants of design at all of a rail shooter, but no, this is not something we imagined as a rail shooter at this point…For example, if you were going straight on a control pad it is very much straight in the game. So while it is not an on-the-rail shooter, you will notice very much some guidance, especially when you are taking turns. We feel these are real positive experiences and additions to the game. If we had thought of making this from the ground up as a first-person shooter there wouldn’t have been nearly as many opportunities for us to bring fresh design ideas. It wouldn’t have been as fun. Similarly if we had aimed at it being solely 2D there wouldn’t have been as many opportunities here. Remember, 2D Metroid, if you just shot at the right height lined up at the target the bullets were going to hit the enemies. A lot of people played those games purely out of habit, because they were so immersed in that world at that time. As you said, some of those games you just couldn’t make now. They have a feeling that has been lost to some extent. But we wanted to bring a little bit of that old feeling back while melding that nostalgia with the evolution of the gameplay experience here.” – Metroid co-creator Yoshio Sakamoto
