Yeah, I remember. For games that didn't have a 'boss mode' key, I created my own custom-short-cut key combos in Windows.
In the mid 80's to the mid 90's I was repairing coin-operated video games of all sorts. Sometimes I'd change game parameters that made it impossible for the player to win. Sometimes I'd alter a game so the player always one. In the office, I'd prank PC users with the opposite of a 'boss mode' and have a game randomly pop-up on their screen for 30 seconds that would interrupt whatever they were doing. Turns out, electronics engineers have less of a sense of humor than accountants. (At least, in that office.)