~Commander Keen 5

Using your desired save game type the following at the DOS
Prompt :-

DEBUG SAVEGAMx.CK5       - Replace x with Save Game Number.
E 17C 5F                 - Will give you 95 Lives
E 168 FF                 - Will give you 255 Shots
W
Q


OR ALTERNATIVELY


An editor cheat  --  By simon Burrows

Here's a hack for the fairly old Apogee game: Commander Keen 5. 
To use it, load the game, save your position in slot one (top) 
then quit back to DOS.

Now, with a Hex-editor such as NU or PC-TOOLS, pop-up the file
SAVEGAM0.CK5 from the main game directory. Then, using the Nos.
in the top-right hand corner as a guide, make  your way to the
following hex-locations and....

  Hex location             Change         To
------------------------------------------------------
Offset 96, Hex 60          00 00 00 00    FF FF FF 37
Offset 104, Hex 68         05             FF
Offest 124, Hex 7C         03             FF

This  will give you 255 lives and shots, and a score  of about
900 million points!!   Go get 'em, sucker!