Quake Wars is a class-based, objective focused, team-oriented game. Teams are based on human (GDF) and alien (Strogg) technology. While the teams are asymmetrical, both sides have the same basic weapons and tools to complete objectives. Unlike other team-based online games (such as the Battlefield series), the gameplay is much more focused on one or two main objectives at once, rather than spread all over the combat area. This allows for much more focused and intense combat situations, similar to the original Unreal Tournament assault mode.
Each player class normally has new objectives show up during game play, many times based around the specific capabilities of that class. The game also has the capability to group players into fireteams for greater coordinated strategy. These fireteams can be user created or game generated depending on the mission selected by the player.
The game has an experience points (XP) rewards system in place, which rewards every player some points depending on the mission completed. This accumulated XP later leads to unlocks which may vary from availability of new equipment/weapons to abilities like faster movement or more accurate weapons. These rewards are reset to zero after the completion of every campaign, which consists of three unique maps, all with a common locale/region.
Source: Wikipedia, "Enemy Territory: Quake Wars," available under the CC-BY-SA License.