Gamasutra, design director James Hague breaks down how his team at Volition developed Red Faction: Guerrilla's many, many missions while working with an enormous, open world where pretty much everything can be destroyed. Beyond the seemingly minor decisions (order of actions within a mission, for instance) being problematic, the sheer enormity of RFG's terraformed Mars and its fully destructible environment drove the game's developer to deliver on the promise of freedom not just between missions, but during them as well. This, as you might imagine, caused quite a bit of a hitch, resulting in the eventual boiling down of some mission objectives to their most basic elements.
"To truly fit into the open world model, missions have to provide the same sense of freedom that the world itself provides. And to make that work takes a change of mindset. It means letting go of being a control freak and instead embracing the chaos that's inherent in open world design," Hague says. For him, game design is often a struggle for how to control the player, and thusly, the player's experience. In the case of RFG, though, he exclaims the team had to "stop caring" about said control. "You can't control what the player experiences every moment. That's not a failure; it's what comes with letting the player do what he wants."
Hague goes into far more detail over four pages of individual mission dissection, so if you're a fan of the game like we are, we'd suggest checking out the whole piece -- it may not be as rewarding as destroying a tower and watching it fall on scrambling soldiers, but then what is?