Access the caged Soul Sphere in level 29, Outpost Omega:

(Note: For a video demonstration of the walkthrough below,
click here.)

Once you have the blue key, go through the blue-keyed door.
As you step through this door, you'll be at the top of a
multi-level maze of passages and platforms.

With your back against the blue-keyed door, the fully
explored maze would look something like this, when viewed
on the wireframe Automap:


      ___
    _|   |_
   |_|   |_|  _._     ___
     [   ]   |   |   |   |
  ___|___|___|___|___|___|
 |   |   |               |
 |___|   |___________    |___
     |   |   |   |   |   |   |
  ___|   |___|___|   |___|___|
 |   |   |   |   |___|   |
 |___|   |___|___|]_[|___|
     |   |   |       |   |.
  ___|   |___|_______|___|     Player arrow ("A")
 |   |   |   |   | ~ [ A ]  -- when pointing away
 |___|   |___|___|   |---|     from the blue door
     |___|           |~~~|
     |"""|              \
      \_/                Blue door


For the walkthrough below, follow the path from point "A"
through to point "G" in this diagram:


Two teleporters
  \   ___   /
    _|   |_
   |_|   |_|  _._     ___
     [   ]   |   |   |   |
  ___|___|___|___|___|___|
 |   |   |               |
 |___|   |___________    |___
     |   |   |   |   |   |   |
  ___|   |___|___|   |___|___|
 |   |   |   |   |___|   |
 |___|   |___|___|]_[|___|
     |   |   |       | B |.
  ___|   |___|_____C_|___|
 |   |   | E | D | ~ [ A ]
 |___| F |___|___|   |---|
     |___|           |~~~|
     |"""|              \
      \G/                Blue door
         \
          Soul Sphere


Step off the platform you're on (A), and you'll drop down
to another platform (B).  Turn left and step down again.

To your right you can glimpse a flashing object through a
slot near the floor.  To your left is a computer screen on
the wall (C).  This is the control for the barrier which
blocks access to the Soul Sphere.

Activate the computer screen like a switch, and quickly Run
down to the Soul Sphere (G).

The barrier only opens for a moment.  If you don't get past
the bars in time, simply go to the teleporters at the other
end of the hallway, and try again.