The developers of Lords of Shadow wanted to take a crack at the front end of "Metroidvania".
The developers of the Castlevania: Lords of Shadow series appear to have been proposing a 3DS and Wii U shooter in the Metroid universe.
First reported by NintendoLife in association with Tamaki (contributor to Unseen64), the Spanish developer was hiring talent from other companies to create a first-person game set in what appear to be post-apocalyptic environments. The proposal would have seen Samus playable as well as up to seven other hunters, and the game was being pitched for both Wii U and 3DS.
The proposal appears to have been designed to allow for new properties to be bolted in if Nintendo turned the project down, as a teaser appeared on MercurySteam's website at the end of July with a male character in a spaceship which may be reusing elements of the Nintendo pitch. The timing of the pitch would have been close to the first public unveiling of Metroid Prime: Federation Force at this past E3.
The full video can be seen below:
Article updated to correct sourcing