Metroid Prime 2: Echoes/Light Beam

Agon Wastes
Now that you have the Dark Beam it's time to get its opposite, the Light Beam

Command Center
Return to the Command Center; this time you can go through the black door instead of going through the floor. Shoot the inactive portal on the far wall to activate it and go through.

Doomed Entry
Get a scan of the floating soccer ball-like creature. There are two platforms in the middle of the room; go around to the back of the one on the left and shoot at the darkened light crystal to reactivate it. Then fire a missile at the statue on the platform to reveal a Lift Crystal. Scan and shoot it with the Dark beam to lower the platform. Hop up the platforms, get the temple key on the left, and continue on to the black door on the next ledge. There is another black door behind the key, but it leads to a dead end.

Somewhere around this point you should be at the 40% scans milestone which opens some bonus features on the main menu.

Oasis Access
Follow the passage; there are Warrior Ing here to make it more interesting.

Dark Oasis
There is a portal near the end of this passage, but you'll have to come back to it because you don't have the light beam yet.

Hall of Stairs
Go past the square pillar and activate the lift crystal on the far side to lower it. This time you can scan the other type of lift crystal after you do. Jump on top, turn around and jump to the ledge, then blast the Missile door.

Save Station 3
Save your game if you want and continue to the next room.