This demo, recorded on ACE difficulty, shows how to expose and destroy the reactor on level 23. There are a couple of puzzles to solve, and three ambushes to deal with.

Our story begins just outside the lower red door, before I have opened it for the first time.

Before opening the door, I go back and leave a little present for a green homer-firing 'bot that is hidden behind a temporary wall. This wall will disappear when you leave the red area through the lower door.

I then open the red door and clear the room behind it, taking a little damage. Entering and exiting the room exposes the green 'bot, and he enjoys my smart mine gift. :-)

Returning to the red area anteroom, I point out the three secret doors that comprise the first puzzle to be solved. The secret door on the right opens when you enter the anteroom via the upper door. Behind this door is a small chamber containing some nice powerups. Entering and exiting this chamber triggers the left secret door (now directly opposite). This chamber contains some more powerups. Entering and exiting this chamber triggers the secret door in the floor. This leads to the reactor and, unlike the other two secret doors, remains open indefinitely.

After executing the above maneuvers, I venture into newly-exposed tunnel in the floor. There is the first of three ambushes awaiting me here: four green "gnats." Annoying, but not too much trouble to clear.

This L-shaped tunnel leads to another small anteroom, and I point out the secret door protecting the reactor when I get there. How to open it? More on that later. First, I open a secret door in the ceiling that not only has a very helpful cloak powerup but is also the only way out! That being the case, I prop open the secret door with a marker to aid my getaway after blowing the reactor.

I grab the cloak and prepare a token of my appreciation for the second ambush, which springs from behind two secret doors, one on either side of the still-hidden reactor. These doors open when I break a plane parallel to the reactor door roughly in the middle of the room. I take a little damage but survive.

At this point, I point out the switch, behind the secret door on the left, that exposes the reactor. But I'm not ready to trip it just yet. First, I go back and grab the invulnerability outside the lower red door. This powerup is ejected by a dying 'bot killed earlier. I can't recall every playing this level where this bot did not eject an invulnerability, so relying on its presence is sound. You just have to remember to save it!

Now, it's time for Mr. Reactor, but he's not alone behind that secret door. He's got a pretty serious welcoming committee, so it's good to be invulnerable. :-) I concentrate on the members of this committee so that they are shrapnel before my invulnerability runs out. Switching to lasers, I take out the reactor, avoiding it's plentiful red blobs, and high-tail it to the exit.

Just before reaching the exit, I see something interesting: a final ambush behind the exit door! A little shot of afterburner, and I'm out the exit just before his missile makes contact! :-)