Iterative game development: What goes into making an effective game and the lessons learned from making two games

Imagine you are told you have two semesters to make a game. You have a team of over ten people ready to help out. You even have the basic idea of what the game will be about. How hard can it be? Well, it is not that hard to make "a game" in two semesters. A competent coder can hack together a game over a weekend. You basically just need a set of rules and a framework in which players can play the game. Now, what if you wanted to make an effective game? A game that really affects the player. Well, this whole one weekend project is not going to suffice. All of a sudden two semesters seems like an incredibly short period of time.