When the normal run through a game provides an insufficient experience I normally begin challenging my own game play by upping the difficulty. In the days of the Super Nintendo and arcade one could just simply select a difficulty setting at the beginning of the game, like mega man 2. However some games do not have a set difficulty setting toggle, which leaves the gamer to utilize their imagination to handicap their quest in order to have more fun. A classic example of this would be my Legend of Zelda no death, no sword, no rings, and 3 life heart run.
Whenever a victory goes above and beyond in some manner, you will find these accomplishments listed here.