bud said:what did they give to the previous prime games?
They reviewed using a different system. There was no overall score, each reviewer gave their own score. Metroid Prime got 5/5 stars from all 5 reviewers. Metroid Prime 2 got 5/5 stars from 4 reviewers, 4.5 from one. The guy who gave it 4.5 was Chris, who seems to be the one who wrote the review for Metroid Prime 3.
Edit: Back then, NP was pretty biased compared to how they are now. It was E3 2005 when they became more than just a Nintendo marketing tool.