1. Any difficulty setting of a game is fine, so long as it lets you complete the game and fight the end boss. I know some games (particularly shooters) only allow you to play so many levels on the easiest setting. Those don't count. But otherwise, I don't care what path or difficulty you beat the game on, and no, you don't have to beat all of them.

2. Saving in the middle and picking up later is perfectly okay, so long as you started the game AFTER replying to this topic. You can't take a previous Mario World save, for example, and then go straight to Bowser, or something like that, though.

3. Continue codes are allowed. Just no invincibility codes, ROM cheats, and I didn't specifically say it earlier, but in Keeping with Rule #1, no using stage select codes or passwords to jump ahead, either.