Yeah, the Mario trilogy had a whole lot of codes that would do a lot of weird stuff. Graphic changes, music changes, etc. Some of them would make the game less playable like the SMB2 suicide code, but they were fun to watch. I used to like using the "debug" code for SMB3 (SLXPLOV IIRC), which accessed what seemed to be a testing function that was left in but normally inaccessible. You could change powerups at will with the select button, and you could also access a gray version of each powerup as well. This version didn't take normal damage, but you couldn't enter pipes while it was active. It was likely designed simply for testing the specific abilities. I could plug that code in plus two of the official codes (infinite lives and Mario could infinitely use items in his storage space; Luigi couldn't) and pretty much be god.
I dont consider it lazy having cheat codes. I get lots of enjoyment playing a game be able to do as I please. I love the fact I can follow the story and run around looking for hidden items without having to worry about an enemy killing me or me breaking my neck in a fall. As for today games being easy, I dont think so. I played Borderlands and it is tedious, especially if you arent at a high enough level and start running out of ammo. I would hav loved to be an instant "god" with unlimited ammo to walk around the wastes of Pandora making everybody bow before my awesomness!
Tedious ≠ Hard. Tedious just means tedious. Whether or not you prefer the easier games of today to the Nintendo Hard of the past is a personal opinion, but outside of rare games like Super Meat Boy or Dark Souls it's an undisputed fact that games are much easier today. Try playing the original Fallout or Legend of Zelda today and see just how many times you die in the first hour alone.