Retro Studios split Aether between light and dark, and Metroid Prime 2: Echoes makes Samus Aran walk both copies of the same map. A light crystal is a safe pocket, and leaving it on Dark Aether starts the suit's drain again.
Beam ammunition is a scarcity the first Prime never pressed this hard, so light and dark shots have to be scavenged. Stepping into Dark Aether drains the suit until a crystal bubble breaks the poison.
Nintendo released this disc sequel in 2004, and a later motion version carried the same hunt. The Ing, the Luminoth, and the temple keys still organize the march.