Rules and Balance

In this past reading, Nielsen talks about how important rules and balance are in a game, and how important they are to a game. He makes the argument that rules "are the most defining characteristic of games; they are the element shared by everything we usually understand as a game, and are the element that sets games apart from linear media such as novels or movies." I agree with this statement because in movies, the makers can take the film in any direction they choose, whereas in games, the player must adhere to the rules. The player can't do anything they want. True, games are getting more advanced, but they cannot be made to give the player absolute freedom. Even in Scribblenauts, a game that gives you a ton of freedom, still has rules. You can mess around with all the different things you can create, but you still need to follow the game objectives to get anywhere in the game (obtaining stars), while if Scribblenauts was a movie or a book, the author basically has no rules and can take the character and do anything he wants with him (rob a bank, give flowers to his girlfriend, etc).
Balance is also very important in a game. "...dominant strategy refers to a strategy that simply is the best one to choose, regardless of what the other player(s) are  expected to do. The existence of such a strategy usually saps the game of potential for choice, thus making it boring." I agree with his statement. I can't think of any wildly unbalanced games off the top of my head, but I remember using a Game Shark on some PS2 games. The cheats were fun for a little bit, but eventually it just got too easy to play. I got bored and I stopped playing. There was no challenge, which is what gamers want. Balance in games achieves that. What unbalanced games can you think of?