There are others which have made some serious advances in the realm of facial expressions, however. The obvious leader in this realm is Valve, which with its Source engine has put a clear emphasis on the importance of the face to expressing emotion and making a connection with the player.
Half Life 2 contains the classic example of the impact facial animations can have during the scene in which Alyx Vance saves an unarmed Gordon Freeman from certain capture. The player, momentarily knocked out by a whack over the head, wakes to find Alyx's warm face greeting him. A connection is instantly made. The same high-quality expressions are attributed to all of the characters to Half Life 2, and go a long way towards making a fantastic sci-fi story into something tangible.
But while the expressions of Half Life 2 are great, Valve's best work is probably in Team Fortress 2. Being a fast-paced multi-player game, TF2 is rarely lauded for its animations. But they are easily some of the best in the entire gaming industry, and perfectly convey TF2's cartoonish mood. Few facial expressions are better then the massive grin that consumes the heavy's face as his minigun fires thousands of rounds at anything that moves.
The importance of these expressions cannot be under-stated. They allow both games to create a powerful and accurate mood which communicates directly with the player. Technically speaking, any Source engine game is unlikely to be the best looking game on the market. But games which make good use of facial animations do far more with far less. As researchers have shown in numerous experiments, expressions are contagious. The feeling of desperation which is created using layers of graphical details, excellent game pacing, and superb writing can just as easily be conveyed with an expression of desperation on a character's face.
A feeling of happiness can also be conveyed in this way, and is perhaps one of the most revolutionary aspects of facial expressions in games. Considering the game industry's obsession with bleak, gritty titles like Gears Of War or Bioshock, the very concept of the smile could cause a revolution in how players think of their games.