Metroid Database.com

Metroid Zero Mission Official Nintendo Player's Guide (2004, Nintendo)

As usual with most Game Boy Advance titles, Nintendo is the only one who published an official player's guide for MZM. But also as usual, Nintendo's guide is slick, cleanly laid-out, easy to understand, and very helpful, with each point in the game explained as well as a guide to all the endings. And like their Prime guide, it contains a complete guide to the unlockable NES Metroid. But wait, there's more -- possibly as a nod to all the hardcore Metroid fans of the Internet who revel in the challenge of completing the game with as few items as possible, N has even included a "15% Walkthrough," showing how to finish MZM with only 15% of the items.