When designing a game intended to evoke particular emotions channeled through an avatar, I focus on something I like to call the emotional mirror. I want the player and the avatar to feel the same feelings at the same time towards the same things, at any given time, using every dirty trick I can.
An Ico panel at GDC first introduced me to this idea, and I was struck by how much they focused on one particular emotional experience, stripping away anything that interfered with that emotion. Filmmakers are very used to doing the same for a symphony of emotions, using costumes, weather, furniture, camera angles, scoring, and much, much more to evoke very specific emotions from very specific scenes. Having such a choreographed scene offers a significant advantage when trying to manipulate emotions, but gameplay is an advantage filmmakers don't have available to them. Designers sometimes miss making use of this advantage because games are too-often built around mechanics instead of an experience. If the intended experience is emotional then the game should be built around that emotion first, with gameplay a tool to meet this goal.
Gameplay can be chosen to enhance the overall mood of a story -- e.g., holding the hand of a girl through puzzles might be more effective at sharing the emotion of "protectiveness" than a first-person shooter. It can also be chosen to enhance particular scenes -- e.g., a character you have been giving resources to for an upgrade stops accepting resources and refuses the upgrade at a moment in the story when the avatar is betrayed by him. It can even be used to control an overall pace -- e.g., puzzles become unnecessarily difficult or easy-but-long-to-complete at the same time the player in the narrative is "wandering" unsure of what next-choice to make before the road to a climax begins. The emotional mirror can lead to interesting design, and interesting observations about some of your favorite games.