The game is set in the near future, where sections of an alien spacecraft have crash-landed in several major cities around the world, including Baghdad and Tokyo.
The player assumes the role of the commander of an armor battalion sent to investigate anomalies that have occurred in the vicinity of the wreckage and gather information on what is happening in the affected areas, as the anomalies are interfering with radar and satellite imagery - and to neutralize any threats that may exist within the anomalies' field of influence.
Players control a convoy of vehicles investigating anomalies around sections of a downed alien spacecraft, which are protected by various types of defensive towers that have to be destroyed. The style of the gameplay has been described as "reverse tower defense", "tower attack", and "tower offense".
Source: Wikipedia, "Anomaly Warzone Earth", available under the CC-BY-SA License.