Infested Planet is a top down strategy shooter where you control a squad of mercenaries on an alien world fighting against swarms of aliens. The team can be boosted with different weapons, health or speed. But the aliens also evolve different abilities to combat you. In the campaign, these mutations are rolled out in specific stages. The game also offers a skirmish mode where the mutations of the aliens are random.
The campaign component of Infested Planet is quick and offers a good way to introduce the player to the various aspects of the games enemies and mechanics. A lot of the missions are varied enough, with standard kill everything type scenarios through to last stands. The game tends to flow at the pace set by the player - that is, if the player is quite aggressive and pushes hard, the aliens evolve faster and the game requires faster adaptation by the player. Conversely, the player can actually take the game at a slower pace, and the aliens won't evolve as fast.
The pace is measured by how many alien hives the player destroys. With each hive taken down, the aliens evolve a new ability. If the player is gung ho and smashes through hives quickly, the game will adapt just as fast. This can leave the player somewhat on the backfoot strategically, as the tactics employed up to that point may no longer apply with the newly mutated aliens.
Overall, the game is quite fun. The variety of alien abilities provides significant challenges, while the upgrades to the player squad also allows for fairly deep strategies. Throw in the quick fire nature of the game, and you get a surprisingly fast and easy to grasp strategy game with a solid amount of punch.
My only criticism is that, for me the game seemed to have an uneven difficulty curve. Some missions were dead easy, while others felt like repeatedly smashing your face into a meat grinder - relentless and painful, but over too fast for you to react. This may be a side effect of my skills in strategy games, but it might be something to consider if you prefer your games to be a little more lenient.