Commander Keen Episode Three Secrets

Commander Keen Three is also a very basic game.

If you hold down the keys C, T, and SPACE BAR, then you will get lots of ray gun charges, a pogo, and all of the keycards.
If you down the keys G, O, and D, then will become invincible and be able to fly with your pogo. You will also be able to walk through walls on the map level.
On the map level, hold down the keys SHIFT and TAB to walk through a level.
To get to the secret level, you must be on the map. Get to Mortimer's level, but do not enter it. Wait by the nearby shore until Nessie comes. Get on Nessie to ride her to the island with the secret level.
Some people have trouble killing Mortimer on the last level. All you must do is shoot all of the purple spark things. Then part of the Mangling Machine will fall of. Now, shoot the heart in the center of the Mangling Machine.
At the beginning of the secret level, pogo up the wall and then proceed forward. You will find a translation of the SGA!
The levels in this game have names that are written in SGA on signs. They are parodies of New York Suburbs. Cho'gall found this secret.
While standing near Mortimer's Base on the map, save your game. Then restore it. Nessie will be to the north of the island you are on. Do not save your game on Nessie's back or you will restore it with the "camera" where you saved the game, but Commander Keen will be at the shore where you get on Nessie. Good luck getting the camera in the correct area :)

That's all I know. If you know of another one, e-mail me.