Cool Secrets

In the last level you can kill the Vorticon Commander, it takes exactly 105 shots.

This trick can only be performed on certain blocks. These blocks are the shiny ones; and it only works on a few of them. The shiny block colors are: blue, green, pink, yellow, and red. It works on pink and red, but not blue and yellow, and I don’t know about green. So to make a block disappear, first you stand under the block. Then have Keen jump up, and just as he is hitting the block turn on the pogo stick. A message box will now appear, and after the message disappears, then the block will be gone.

The name of the gum that you can pick up throughout the game is Three-Tooth Gum. Plus, the name of the lake south of the Perilous Pit is Three-Tooth Lake. Now, if you know your Greek and Latin roots, you'll realize that TRI means THREE (as in tricycle) and DENT means TOOTH (as in dentist). Put 'em together and you get THREE TOOTH GUM, or TRIDENT GUM, a popular brand of gum in America! Therefore, the Commander Keen powerup item called Three-Tooth Gum is a well-hidden, funny reference to Trident Gum! As for the Three Tooth Lake deal, Posedion is the Greek god of rivers and lakes, and he carries a three-pronged spear called a TRIDENT! See the relation? Lake-god carries trident, lake is called trident!

Go to Defense Tunnel Teln, then go to the upper right corner, Robo Red will be to your left going back and forth on a ledge, shot him when he is on the edge of the ledge, and he will go a little bit off if you keep on shooting him he will move still farther, once you stop shooting him he will shake back and forth making a blur.

You can make Keen pogo backwards, just jump in any direction, lets say left, then press right (don’t hold down the right key), even though Keen is now facing right he will for a fraction of a second still be going left, during that time turn on your Pogo-Stick and hold down the left key, if this is done right Keen will be pogoing left backwards.

Enter the Perilous Pit and go to where the Bounder is, then shoot the bounder when he is bouncing over the pole. The stunned bounder should be lying in front of the pole, now jump on the bounder and try to climb down the pole. Keen will spin in circles trying to get down, but the bounder blocks his path.

If you go to Miragia and hang on the side of a ice block when the block becomes transparent Keen will still hang on, another way do this is to have Keen look up or down...

Here's a fun patch.
Extract your Commander Keen 4 executable (keen4e.exe) with PkLite or a similar tool and do the following patches with the hexeditor of your choice.

Offset 0x333a8: change AE 00 AE 00 to 40 01 3B 01
Offset 0x333c6: change AF 00 AF 00 to 41 01 3C 01
Offset 0x333e4: change B0 00 B0 00 to 40 01 3B 01
Offset 0x33402: change B1 00 B1 00 to 41 01 3C 01

Extract your Commander Keen 4 executable (keen4e.exe) with PkLite or a similar tool and do the following patches with the hexeditor of your choice. I use Unlzexe.

Offset 0x3299E: change 39 01 39 01 to 98 01 98 01
Offset 0x329BC: change 3A 01 3A 01 to 98 01 98 01
Offset 0x3365C: change 35 01 37 01 to A2 01 94 01
Offset 0x3367A: change 36 01 38 01 to A3 01 95 01
Offset 0x33698: change 35 01 37 01 to A2 01 94 01
Offset 0x336B6: change 36 01 38 01 to A3 01 95 01

In the secret level when you reach the end there is a pole and a Blooglet, climb to the bottom of the pole and when the Blooglet runs under you press the down key, and if you did this right Keen will be riding the Blooglet. This can be done elsewhere as well.

You can make Keen pogo backwards, just jump in any direction, lets say left, then press right (don’t hold down the right key), even though Keen is now facing right he will for a fraction of a second still be going left, during that time turn on your Pogo-Stick and hold down the left key, if this is done right Keen will be pogoing left backwards.