When I first played this, I liked it a lot, but was rather frustrated with going back-and-forth through the light and dark worlds and the ammo system. After this playthrough, I'm pleased to say that those are not as much of an issue as I remembered. It really is an amazing game; it just lives in the shadow of Metroid Prime. While Prime is still my favorite game to this day, Echoes does a lot right, especially with its puzzle and boss design.