Unseen64 recently updated its comprehensive article about the development of Metroid Prime. The site has plenty of details about what was cut and changed in the game, ranging from bosses to power-ups. There’s also information about various redesigns for Samus, the change from third-person to first-person perspective, and more.
Here’s one notable excerpt concerning a Kraid boss battle that was removed from Metroid Prime:
As mentioned above, Kraid was a part of the original plan for Metroid Prime. We understand that he was slated to be added to the last act, as he was cut towards the end of development. At the time, he had come a long way from the more traditional route that was first being considered.
In this 3D model by Gene Kohler, he was redone with a metal helmet, masking the majority of his face. Due to this feature, fans have taken to calling this infamous render ‘Meta Kraid’, although, in truth, no such title had been assigned.
Contrary to certain speculation, Kraid was, in fact, very early along when work on him ceased, as one ex Retro employee recounted:
“Kraid was really just some ideas and a first pass model. We were about to start work on him when he was cut. The overall idea was to have Kraid at one end of a large cavern, and some rickety platforms at the other end that Kraid could reach out to and tip over. He would also fire missiles at you from his belly ports. As I recall you would have to climb to the top and trigger something to collapse on him several times. There were probably other stages but I don’t remember them.”
Despite appearing in the Phazon Mines in Kohler’s image, it was never defined whereabouts in the game he would actually be encountered either. Speaking to MythicaHQ in 2004, he explained that Kraid’s absence was a casualty of time restrictions:
“I had completely finished modelling and texturing Kraid. The level that he was to be included in was well underway to being designed. There just was not enough development time remaining to fully implement all aspects of the scenario that were needed to pull off a highly polished\fun gaming experience… animations\effects\programming\etc. It was decided that Kraid was not imperative enough to the Metroid Prime project to run the risk of pushing up the release date in order to fit him in.”
Unseen64 also posted several clips of things such as cut creatures:
For plenty more on Metroid Prime’s development, head on over to Unseen64.