1up's interview with Metroid co-creator Yoshio Sakamoto and Team Ninja head Yusuke Hayashi.
"1UP: When I think of the two series, they seem very different. Metroid is very slow, methodical, exploratory, while Ninja Gaiden is very fast, violent, and action-oriented. How do you reconcile those two and create something that takes advantage of your strengths, but still feels like a Metroid game?
YH: We want to try and take the best of both. As you progress through the game, there will be more action-oriented, faster-paced sequences. But then you'll have your careful, exploratory parts of the story as well. We actually used it to our advantage to try and marry the two concepts together. "
http://www.1up.com/do/previewPage?pager.offset=0&cId=3174587&p=44