Figuring out a game of the decade is a tough task because each year the quality improves. And in the past 10 years, video games exploded. Gamers saw developers make good on the promise shown in the 1990s as releases began to look more like playable Pixar cartoons and studios harnessed the power of the technology to invent new types of gameplay. In this decade alone, we saw the introduction of the Wii, PlayStation 3 and Xbox 360.

With video games advancing by leaps and bounds, where do we begin to judge? Is it the quality, artistry or innovation? Or maybe it's the storytelling. When putting this list together, we looked at a combination of these traits with an eye toward impact. The following games set the tone for the decade:

1. "Deus Ex" (2000): Before Sept. 11, Warren Spector's shooter was eerily prescient about this decade in more ways than one. The cyberpunk story about an anti-terrorist agent investigating a global conspiracy offered gamers a hint of the themes that would dominate the next 10 years. The game's mix of shooter and role-playing elements have been mimicked, but the amazing level design stands far above anything that's been created. Many have tried to duplicate "Deux Ex's" gameplay, but none have succeeded.


2. "Grand Theft Auto: San Andreas" (2004): "Grand Theft Auto III" gave us open-world, do-anything gameplay, but it's the third and most controversial iteration where Rockstar Games perfected it. Set in the 1990s, "San Andreas" is the largest world that the team has created, and it's still the genre gold standard today.

3. "World of Warcraft" (2004): It's not the first mass multiplayer online RPG, but Blizzard's game is the one that brought it to the masses. It turned a burgeoning genre into an worldwide phenomenon and became a cultural touchstone for nerds everywhere.

4. "The Sims" (2000): Will Wright's take on suburban life opened video games to a whole new audience. It was also one of the most profitable franchises of the decade, spawning its own division in Electronic Arts.

5. "Star Wars: Knights of the Old Republic" (2003): BioWare's take on the Star Wars universe ended up being the best single-player RPG in years. It established the morality-based gameplay that's been the studio's calling card for the better part of a decade.

6. "Guitar Hero" (2005): Harmonix and RedOctane's music-rhythm game started off small but quickly exploded, changing the music and video game world forever. In the past few years, the genre it popularized evolved into "Rock Band," "Guitar Hero World Tour" and "DJ Hero."

7. "LittleBigPlanet" (2008): No other release changed how fans looked at games than Media Molecule's platformer. Its ethos of playing, sharing and creating gives us a glimpse of what's to come in the next 10 years.

8. "Katamari Damacy" (2004): Keita Takahashi's masterpiece made quirky cool again. At a time when games were becoming more complicated, "Katamari Damacy" showed how a simple but fun concept like rolling a ball can trump games with complex control systems and a plethora of items.

9. "Devil May Cry" (2001): Hideki Kamiya showed the world how to make an action game in 3-D. Aside from exuding a new sort of cool, the game paved the way for dozens of other titles, including "God of War."

10. "Bejeweled" (2001): This puzzle title, which has been ported to every system known to man, joins "Tetris" as the quintessential casual game. The match-3 gameplay has become so universal that it can be found on anything from Flash games to the Xbox 360.

11. "Call of Duty: Modern Warfare" (2007): When Infinity Ward moved its franchise from World War II to contemporary times, it created a significant shift in shooters. The new setting and its compelling online component set the trend for other shooters.

12. "Halo" (2001): Bungie's shooter put Microsoft's Xbox on the map. It was also the console player's definitive online multiplayer game for years.

13. "God of War" (2005): David Jaffe's epic about a Spartan warrior who makes a Faustian deal with the god Ares is also one of the best new franchises of the decade. The final game in the trilogy will be released in March.

14. "Wii Sports" (2006): This is the game that made the Wii a hit. Showing how motion-controls can reach a new demographic, "Wii Sports" put Nintendo on top of the console heap.

15. "Shadow of the Colossus" (2005): Fumito Ueda's "Ico" showed the potential of games as art, but his haunting masterpiece about a warrior trying to resurrect a young maiden is where his vision reached the masses.