Just in case anyone else has had this problem playing the game:
When you get to the 8th level "River of Death" you have to jump from the raft (under fire) to a landing dock. I found the task impossible without getting wasted. So:
Before you get that far down the river, and while the game is in progress on the monitor screen, you hit the T. It doesn't show, just a blinking dot. Then while it's blinking, you type in the code you want; and, do it for each additional code you want, always hitting "enter" immediately afterwards. The blinking dot will be at the bottom left of your screen. When you hit enter, it will reveal your status in the upper left screen. Example: JohnWayne typed in reveals you're now in the God Mode. And when you save, it keeps it in memory. The reason I save, is because if you fall in a hole, or go over a waterfall, although you're still alive, you can't escape the trap, so you have to start over from where you last saved. ---JackC