Dino Dini, probably most known as the creator of Kick Off, a Football (soccer) game in the 16-bit era, is now a lecturer at the IGAD programme of NHTV Breda University of Applied Sciences in the Netherlands, and teaches Game Programming. He was at GDCE 2009 talking about how constraints give form to a design and how it is important for a game to keep it’s integrity.
In the talk, Dino talked about how there are both non-negotiable constraints and negotiable constraints in a design. Basically, breaking the non-negotiable constraints will change the identity of the design, but changing a negotiable constraint will not. It is important for a design to maintain its identity in order to have integrity as successful designs always have integrity. This is true in other things as well, such as movies. A movie should have integrity and keep its identity in order to be successful.
As an interesting example, Dino showed how the key non-negotiable constraints of Kick Off define the game.
At least after seeing the game, it is easy to see how these constraints really give form to the game. It is easy to see how a game created in the era when Kick Off was made, following these constraints, would turn out to be a game like Kick Off.