Find a spot where you want to go up, then jump. While in midair, shoot down as you are falling. . If done correctly, Keen will be standing about a one shot width off the ground. Simply look up and shoot. You will take off straight up at the speed of your shot. Note: Some practice is required to get the correct timing.
At the start of the Parsnip Pass level, go up to the top where there is a log and two squashes on it. After that, jump high enough to get the squashes attention, and wait for them to jump over to the rightmost side of the screen. Fall down with them. Once you hit the bottom, where there is an island with water on the left side, stand next to the right side, which is a wall that you cannot see. Wait for the squashes to fall and hit you. When they hit you, you will start to fall asleep, but you will hit the wall and the "Loading The Land of Tuberia" message will appear. You will not lose a life, but Parsnip Pass will be completed.
Press A + 2 + ENTER during game play to enable cheat mode in Commander Keen 4 or 5. Activate the following cheats by pressing F10 and the following keys simultaneously. Note: You will lose a life if you leave the level with the "No clipping" code enabled. Activate the "Record demo" code again to save the demo:
CHEAT FUNCTION - KEY God mode - G Level select - W Flying jump - J No clipping1 - N 99 ammo, 3000 points - I Sprite test1 - T Record demo1 - D Add 0-8 VLBs1 - V Display memory usage1 - M Level skip1 - E Slow motion mode - S Show hidden areas1 - Y Set border color 1-151 - B Show active and inactive object numbers in level1 - C