For a long time I used to play the games with cheats. Back when we had little to no access to original games on 8bit computers where I live and on C64 almost every game was cracked and had cheats. I was playing the games like that. No challenge, just having fun going through the game, destroying everything on my way.
The games should have god mode. I wouldn't mind if it was stated somewhere in the description or having some icon, just as games have "singleplayer", "multiplayer" info. Even games with leaderboards should have that. The result would be ignored but it could be quite useful for training.