Was Retro Working On Metroid 1.5?
According to documents supposedly leaked from a level designer for Retro Studios, the Metroid Prime developer had pitched Nintendo on a game known as Metroid 1.5 -- a title set between Metroid Prime and Metroid Prime 2: Echoes.
A sharp-eyed member of the NeoGAF forums discovered this massive proposal document from 2002. The game was set to begin "immediately after Samus takes off from the surface of Talon IV" at the end of Metroid Prime and would follow the bounty hunter as she explores an alien spaceship in a parallel dimension.
Throughout the course of the adventure, Samus would be taunted and hunted by the ship's evil AI program. Samus would maintain all of her powers from Metroid Prime, but the AI program would limit her abilities in different ways in each area.
The game world was planned to be the size of "the ruins and the mines" from Metroid Prime combined, with expanded use of scan mode and ball mode. Interestingly, the document pegs the game as "more about solving puzzles" -- essentially the opposite of Metroid Prime 2: Echoes, which ended up being more combat-heavy than the rest of the series.
The document also has a list of different AI personalities that would manifest throughout the ship. For example, "The Killer" would appear in more combat-heavy areas, whereas "The Child" would be in puzzle-centric rooms.
Also interesting: The document mentions a possible co-op mode in which Samus would create an android double of herself that could be controlled by another player.
Visit the GAF thread for more info and pictures of the project that was apparently either shot down by Nintendo or given up on internally at Retro. Whatever happened, I'll say what must be said: It sounds better than Metroid: Other M.