Metroid Prime was developed as a collaboration between Retro Studios and Nintendo EAD and R&D1 members. Retro Studios was created in 1998, by an alliance between Nintendo and former Iguana Entertainment founder Jeff Spangenberg. After establishing its offices in Austin, Texas in 1999, Retro received five cancelled game ideas for the future GameCube, despite not even having development kits. It seems that one of these project, Retro Studio’s Action Adventure game set in a SciFi settings, was used as a base to create the first prototype of Metroid for the Gamecube.
The game was originally envisioned as having third-person perspective gameplay, but this was changed to a first-person perspective after Miyamoto intervened, causing almost everything already developed to be scrapped. Among the reasons for leaving the third-person perspective were Rare’s trouble with the camera in Jet Force Gemini, shooting in third-person “not being very intuitive” and exploration being easier using first-person.
Kraid was originally intended to make an appearance in Metroid Prime as a boss, and was modeled and skinned by Gene Kohler for that purpose. However, time constraints prevented it from being included in the final version of the game. Though the beta model displays him inside Phazon Mines, contrary to popular belief, he was not, in fact, replaced by the Omega Pirate. The Area he was supposed to appear in was never put into the final release, suggesting that the Phazon Mines were originally going to be bigger. Of note in the Prime Kraid’s appearance is his head. It appears to be covered by a metal dome in the picture. It is possible Kraid was meant to be Meta Kraid, as Meta Ridley is in Prime. – [info from Wikipedia]
Also, in the third video you can notice an early menu brackground, in which the game was subtitled “First Person Adventure“. A beta model of the Phazon suit, a beta Gravity Suit and an unused speech audio file (check the 4th video) were found in the game’s code. The inside of Samus’ ship is also textured a bit.
Thanks to a model viewer created by Interdpth and Revel8n it’s possible to find various unused models hidden in the game’s code. You can download the Metroid Prime model viewer (mpxviewer) in here. If you are able to find more unused models, please let us know!
Thanks to Robert Seddon, GF_Kennon (from Metroid Construction) and Interdpth for the contributions!