Cheat Codes

Invasion of the Vorticons
Bypassing a City
While walking against a city press the keys "Shift, Tab" and you will walk right through the city.

Flying and Invisibility
You can fly and become invincible, by holding the keys "G, O, D" down, (on some computers you have to press this key sequence really fast and a whole lot of times for this to work, but I can be done) and you can only fly when you have your pogo on, and you will die if you fall in a pit. Also this cheat will deactivate every time you leave a level.

Pogo-Stick, 100 Ammo, and all Key-Cards
Hold down the keys "C, T, Space-Bar" and you will get a Pogo-Stick, 100 Ammo, and all Key-Cards (if you collect more than 100 ammo and activate this cheat your ammo will go back to 100).

Keen Dreams
Debug mode
Press the key (F10) with of the any of the letters below.
G - God mode (You're invincible)
I - Free Items (99 ammo, 99 keys, 99 bombs)
W - Level Warp (use levels 1-15)
J - Jump mode (You will fly, but Keen will fall if he hits a ceiling)
Goodbye Galaxy
Lots of Ammo, Extra Life, and all Gems

If you hold down the keys (B, A, T) you will get 100 ammo, all gems, and a extra life (you can enter in this code as many times as you want but you will never get more than a 100 ammo).

Debug Mode
To activate the debug mode press the keys (A, 2, ENTER). Now you can activate any of the following by pressing the key (F10) with the selected letter.
B - Set border color (1-15)
C - Number of active/inactive objects in the level
D - Record a demo
E - End or finish the current level
G - God mode (you can't die)
I - Free items (add 3000 points and 99 shots)
J - Jump mode (you can fly anywhere)
M - Memory usage display
N - No clipping (fall through ground)
S - Slow motion
T - Sprite test display
V - Add 0-8 VBLs
W - Warp to any level
Y - Reveal hidden areas (shown in normal color)
Aliens Ate My Babysitter
Debug mode
Press the key (F10) with of the any of the letters below.
B - Set border color (1-15)
C - Number of active/inactive objects in the level
D - Record a demo
E - End or finish the current level
G - God mode (you can't die)
I - Free items (add 3000 points and 99 shots, all gems, and all items)
J - Jump mode (you can fly anywhere)
M - Memory usage display
N - No clipping (fall through ground)
S - Slow motion
T - Sprite test display
V - Add 0-8 VBLs
W - Warp to any level
Y - Reveal hidden areas (shown in normal color)
Commander Keen - GBC - GAMESHARK
(By: Tony Gies)
Infinite Lives
916334c9

Infinite Continues
91633dc9

Max Score
917f35c9
919636c9
919837c9

Have All Keys
91ff95c9

Have All 3 Crystals
91ff3ac9
91ff3bc9