It's easy to think about games in terms of winning and losing. They are a series of increasingly complex challenges that you either pass or fail. Reaching a fail state leads the player to a bitter few seconds of rebuke, before he or she is presented with the same problem again. This is the oldest and most basic stricture of game design, from Jacks to Go.

The inherent power of video games is their ability to make take these rudimentary principles of interaction into an authored space that affects a player's senses. I remember teaching my younger cousin how to play Super Mario Bros. when we were kids. At every jump she jerked the controller upwards, and she cried out in mock pain upon falling into a lava pool.

Immersion is a concept that appears with great frequency in game design, but the means to conjure it can be elusive.

For all the attention to detail put into art and animation, inconsistent AI or awkward lip-synching can make players roll their eyes. Likewise, a grainy DS Pokémon game on the Nintendo DS can hold young players rapt for hours.

How do games hold players' attentions without running aground on disbelief and incredulity? How can designers turn a feeling into lines of code, and then into an experience that moves a player to keep pushing through an interactive fantasy?

It Moved Me, and It Moves Me Still

Movement is the most basic element of 3D game design. You can create a world and a series of rules to govern the objects in that world, but until there is a cipher to move among those objects the game is lifeless. Movement is also the first and most persistent layer of interaction which developers are able to communicate with players.

"Movement is the core of the game and because of that we focused heavily on that until we got it right," said Owen O'Brien, senior producer on DICE's Mirror's Edge. "The movement was the first thing we developed before Faith, before the story, before anything else."

Without a cutscene, dialog box, or instructional manual, character movement can communicate a lot of dramatic qualities. In Mirror's Edge, the emphasis on momentum and slight left to right movement of the camera with each step, subconsciously draw players towards its acrobatic gameplay.

Killzone 2 and Gears of War give players a sense of constraint with the lumbering movement animation that subconsciously encourage methodical play and special attention to cover.

"We had a series of designer-constructed test rooms for every aspect of player movement so we could prototype everything in exhaustive detail," said Michael Kelbaugh, president and CEO of Retro Studios, discussing the development of Metroid Prime. "Only when we had that really mastered did we begin the bulk of world construction."

It can be tempting to rush past this stage of the prototyping process to get to the actual content creation, but having an evocative movement system can be a turnkey in evolving a staid genre. Need for Speed Shift took one of EA's annual franchises out of the oxidizing conventions of its predecessors by focusing on first person racing.

After bottoming out with 2008's Need for Speed Undercover, Shift added twenty points to its Metacritic score on a wave of largely admiring reviews.

"The key aim with the cockpit view was to translate that raw intensity that you feel in a real-life race car to a player holding a control pad," said Andy Tudor of Slightly Mad Studios, describing Shift's design. "At high speed we do a combination of things; blurring the cockpit out to make you concentrate on the upcoming apex, camera shake, and even having the driver's hands shake and grip the wheel tighter as they try to control the car. All these combined give you the cues you need to get an exhilarating sensation of speed."

These ambient flourishes suggest consequence to the in-game action that has a real-life counterpart. It's one thing to see your in-game performance evaluated through abstract meters in a HUD, but it's much more frightening to think a mistimed input could send you through the terrible experience of a full speed car crash in first person.

It can be easy to think about what the player is supposed to accomplish, but the best games also focus on what they want their players to feel while they busy achieving objectives.

"We wanted the player to feel as if they were actually inside Samus' helmet," said Kelbaugh. "Our first idea was that beads of water could appear on the faceplate when Samus moved into and out of water or steam. When this test worked so well, we began to look for more opportunities to use this function, like enemy goo, Samus' reflection, and so on."

With the recently released Dead Space Extraction, Visceral Games and Eurocom invested a lot of time in motion capture, facial animation, and creating a library of first person movements to create a more cinematic horror experience.

"We were pretty fortunate that Eurocom has a really fantastic motion capture studio right there at their offices," said Wright Bagwell, creative director at Visceral. "We basically had one of the actors carrying the camera around and they were just acting out these big scenes we had designed."

"We discovered early on that if you have a guy running around with a camera and you take that capture straight out of the studio, it can be pretty obnoxious."