Metroid Prime 2: Echoes, like its predecessor, contains several subtle easter eggs and fun facts for observant players. One notable easter egg is the presence of Metroid Prime 1 save data bonuses. If you have a Metroid Prime 1 save file on your memory card, you can unlock Fusion Suit textures for Samus's Power Suit in Echoes, offering a cosmetic change. This is a small nod to the previous game and Metroid Fusion.
Another fun detail involves scanning certain creatures. Some enemy logbook entries contain humorous or intriguing descriptions that add flavor to the world. Keep an eye out for subtle environmental storytelling, such as the remnants of Luminoth civilization or the tragic fate of the Galactic Federation Marines, which are often conveyed through scannable data logs and visual cues. The game also features a 'secret ending' for achieving 100% completion, providing additional lore and a glimpse into future events.