Planets Under Attack

In Planets Under Attack players need to expand their control over an entire planetary system, completing objectives and eliminating any enemies encountered along the way. Besides a campaign mode, there's also a skirmish and a multiplayer mode, where you can choose from a variety of missions and options. A player usually starts with one or a couple of planets, each possessing one attribute - population. In order to conquer a foreign planet, a greater number of units than the one hosted by the targeted planet must be sent, taking into account population regeneration and the ability to send reinforcements, as well. When attacking, the game draws population from all the player-controlled planets and redirects them toward the target. It's possible to switch planets to a defensive mode that prevents them from contributing to an offensive. On the other hand, the robots must specify both the source of the attack and the target planet. Planets produce sollars (money) when playing as humans, or energy as robots. The total amount of sollars or energy limits the number of units that can be sent into an offensive. While attacking, the planets are unable to refill this common pool of money or energy.

There are four types of planets that can be controlled by the player. Metropolis is the only type that produces population, the space fortress attacks any hostile forces that enter its range, the bank planet generates money in addition to the amount received automatically, while the powerplant does the same for energy when playing as the robots. For the sake of defense, population can be transferred from the metropolises to any of the other planets. The planets (except the banks) can be upgraded in order to increase the maximum population or the defense capabilities of the fortresses. Upgrading a planet requires a specific amount of sollars, or population, in the robots' case.

Several mission modes are available in both single- and multiplayer. While in Elimination all the foreign planets must be conquered, the Capture mode involves overpowering several designated ones before anyone else. In both Domination and King of the Hill modes, the players must hold the planet marked with a whirlwind for a specific amount of time. The only difference is that in the first mode the timer can be resumed later, in case the planet was lost, while in King of the Hill the control must be continuous. All modes can be won by eliminating all opposing forces. There are three modes exclusive to the campaign.

The campaign sees ruined businessman Mr. Goodman exploring the hidden corners of the Universe in search for new opportunities and fortune. The player navigates around the galactic map from mission to mission. Certain paths are blocked and can be unlocked only by collecting stars. More stars are rewarded by completing missions at higher difficulties, which add other objectives besides the main one. Exclusive to the campaign are the Payback, Boss Battle and Swarm modes. In Payback, the player must simultaneously pay a specific amount of sollars to debt collectors, headed by Mr. Norrell. At the same time, the collectors will start conquering the player's planets, one by one, and the only way to delay this is to pay more money. The Swarm mode features several neutral planets infected with alien eggs, which after a time will hatch and attack all other factions on the map in a frenzy. In Boss Battle, the main opponent is a boss planet with a special move, like transforming an enemy planet into a friendly one instantly. The goal is to conquer it before the time runs out.

Planets Under Attack features a level-based progression system, where higher levels give access to technologies that enhance different characteristics, such as a boost in population, income or the ships' speed. Up to three technologies can be activated at the same time. Additionally, a player can also earn medals, rewards and ranks by playing and completing missions.