To activate, press: ALT+\ during the game.  You will be prompted to "ENTER
CODE:"
 
Enter any of the codes below:
 
version       - Prints version #
version(id)   - Prints version # with some extra info
hello         - Prints "HELLO?"
turbo         - Turns turbo mode on
superuzi      - Gives you the Super UZI.
garble        - Cheat-code garble on/off : Allows you to see the code
                you're typing in.  Instead of "*"
firepower     - Gives you all weapons
bandaid       - Refills your power/armor
nextmission   - Go to next mission
icantsee      - Puts a viewscreen at the top right
whoami        - Tells who you are
counters      - Puts numbers at the top left

(Quoted from a post by Bernd Wolffgramm - uzs691@ibm.rhrz.uni-bonn.de)