A portion of a Eurogamer interview with MercurySteam's Enric Alvarez and Dave Cox...
E: Is the rumour that you created a Metroid prototype for Wii U and 3DS also bullshit?
Enric Alvarez: That's more bullshit.
Enric Alvarez: People have a lot of imagination and time to think about stuff, but that's not necessarily the truth.
E: So you're saying, categorically, you did not work on a new Metroid prototype for Wii U and 3DS?
Enric Alvarez: This is exactly what I'm saying.
Dave Cox: We're primarily working on Raiders. We are doing other things. But Raiders is the focus of the studio right now.
Enric Alvarez: I think this one grew from an interview we did when we were finalising Mirror of Fate. While doing an interview, somebody asked us about what other game we would like to do, and I think the Metroid thing came from that. Or it was about the Metroid influences in Mirror of Fate. The rest is pure invention.