Metroid Prime 2: Echoes/Seeker Launcher

Temple Grounds
You'll be taking a break from Torvus for a bit since the next upgrade is in the Temple Grounds and there is an optional one after that in the Agon Wastes.

Meeting Grounds
By now the help system may be pointing to an area directly under the Great Temple. But if you try getting there directly from the Service Access you run into a dead end. Instead, go to the Meeting Grounds and find the U-shaped passage there. As you might guess it's actually a half-pipe, so boost up to one of the ledges above, jump over if necessary, and roll into the Morph Ball tunnel there.

Service Access
You're now in a tunnel in the upper part of the room. As soon as the camera changes to side view, stop and look for a row of disappearing blocks. Use the Boost Ball to zip across them just as you did in Dark Arena Tunnel. Continue to the next room.

Path of Honor
You're in a track in the upper part of a passage. This is where you would get stuck if you tried to get to the area under the Great Temple directly.

Hall of Honored Dead
The upgrade you seek is here, but there is a force field around it and you must solve a bit of a puzzle to get to it. There are four Spinners of different colors, each of which controls two of five rings around the force field in the middle. If the rings are number from inside out then
 * The Red Spinner controls rings 1 and 2.
 * The Yellow Spinner controls rings 2 and 3.
 * The Aqua Spinner controls rings 3 and 4.
 * The Purple Spinner controls rings 4 and 5.

You must turn each spinner until it locks into a new position, otherwise the rings will spring back to where they were. Call this a 'move'. When a ring is in the right position it starts to glow, and you need to get all five rings in the right places. You're not bumped out of the Spinners automatically, so drop a bomb when you want to get out.

The best strategy is to use the Red spinner to get ring 1 into place, then the Yellow spinner to get ring 2 into place, and so on going from the inside out. You could also go in reverse order just as easily. The upshot is the number of moves for each spinner is Red - 1, Yellow - 3, Aqua - 1, Purple - 2, but if you've already gotten the rings out of their starting position you'll need to use the strategy above since there's no reset option.

When all the rings are in the right places, some lenses appear with focus beams of light on the force field and break it; now you can get the Seeker Launcher. As an additional bonus, your Missile capacity in increased by 5 when you get the launcher. As a weapon it's not very useful except against a few enemies, but you need it to open Purple doors. The idea is to hold down the missile firing button until an orange reticle appears. Then you can lock on to targets as they come into range, to a maximum of five; the reticle turns pink when you're at the limit. Release the firing button to fire missiles at all the targets at once.

You might want to try it out on the Sand Bats that are flying around overhead. The bats keep respawning and drop Missile ammo so don't worry about running out. When you've had enough, get to the Purple door and use the Seeker Launcher to target the five lights around it, then fire to blow open the door.

Path of Honor (cont.)
This is the main part of the hall leading back to Service Access.