The following procedures tell you how to get to the secret levels in episodes
4-6 of the Commander Keen series.  The text was adapted from a procedure
written by Joe Siegler.

Episode 4:  To get to the Pyramid of the Forbidden (the hidden pyramid with
the hand on it), go to the Pyramid of the Moons level, get the yellow crystal
and go to the room that has twelve inchworms in it.  To the left is an open
passageway with some inchworms to the left of it.  All the way to the right of
this bottom room is a door that needs the yellow crystal.  Go through the door
and flip the switch behind it.  The left trapdoor will close over allowing all
the inchworms to gather.

Get the twelve inchworms together in one spot.  When you are near them, they
will follow you; if they are off-screen, they'll lose track of you.  When
the twelve are gathered together, a foot will form above your head.  Jump on
the foot, and it will take you to the hidden pyramid.

While you're in the hidden pyramid, you won't be allowed to play any other
levels until you finish that one.  When the hidden pyramid level is completed,
the foot will be there again.  Jump on it, and you'll be transported to the
outside of the Pyramid of the Moons, and you can continue with your game.

To get outside the Pyramid of the Moons, you need to go all the way to
the left of the room where the inchworms are.  There will be four guns
in the ceiling shooting down.  To the left of them is a hole in the
ceiling you can jump into.  Do that, and there will be a pole in there (that
you can't see) that you can grab onto.  Save your game, since it's easy
to die in here.  Follow the passageway and you'll see a door.  You can
go into that door if you want; there's a free life.  Come back through
and jump into the ceiling above that door, and follow a passageway in
the wall.  You'll come out to a doorway with a bunch of ice cream
cones in front of it.  Go through that door, and you're outside the
pyramid.

However, if you exit this level before going to the hidden pyramid,
you won't be able to get to the hidden pyramid, since this level
(Pyramid of the Moons) will be considered finished, and you won't be
able to get back in.

Episode 5:  Stand in the archway near the end of the level in the "Gravitional
Dampening Hub".  You will not be able to see yourself in there.  You'll need
to do the down jump maneuver, which is holding the down arrow and pressing
jump.  You will fall into the floor below you.  You will then need to walk to
the left, as far as you can go.  Since you will not be able to see yourself,
the only way to know it's working is if the screen starts moving.  If, when
you start moving left, you appear again next to the arch, you didn't do the
down jump maneuver right.

Once you walk to the leftmost part of the level, you'll fall all the way to
the bottom of the level.  Once you stop falling, walk to the right, and you'll
appear again.  SAVE YOUR GAME HERE!   The passageway that you're in leads to
a teleporter, which will take you to the secret level.  There are no more
secrets along the way here, but there is a LOT of stuff that will kill you,
which is why you should save beforehand.

Also, there is a bug in the secret level of Keen 5.  Once you get there, if
you look around hard enough, you'll find a transistor that you're supposed to
pogo on and break.  Sometimes you'll not be able to break it.  Apogee never
found why this happens.  Sometimes it will work; sometimes it won't.  If you
do break it, the end game story will say that the Shikadi ship blew up;
otherwise, it will say that it got away.

Episode 6:  This is the easiest one of them all.  Right before the final level
of the game, when you're on the world map, you'll see a somewhat large blue
towering thing that looks like a cross between a hut and a mouth.  If you look
beyond it, you'll see a yellow fence.  If you walk through the mouth and out
the other side, you'll come to the fence (don't enter the level; going in the
mouth and pressing space will put you into the level).  Stay on the world map,
and wait there a minute or two.  A spaceship will come around, pick you up,
and will take you to the secret level.  When you're done with the secret
level, wait for the ship again, and it will take you back.  An English
translation of the Galactic Alphabet is in a hidden area in this level.