Changing Rocket Speed
      Open up DeHacked. (Press [alt + enter] if you want full screen.) You should be in the "Things" menu. (If you're not, press [F2].) In the top-left corner, click "Thing Number." Scroll down until you see "Rocket (in air)." Click on it. In the left-middle box, click the number next to "Speed" and press [enter]. Now just type in any number. Let's say 1. Press [enter]. You just changed the rocket's speed from 20 to 1. Now press [w] (which writes the changes). Press it again to make the "Changed data written to exe" message go away. Now press [r] to run the edited game.
      Once you are in the game, type [idfa] (the all weapons cheat) and press [5]. Fire a rocket and see the results!