In 2018, the multiplayer tactical shooter Tom Clancy's Rainbow Six Siege launched a temporary Outbreak event. It united operatives from the game against alien parasites that appeared in Mexico, but Ubisoft wanted to develop this idea. So four years later, a great shooter called Rainbow Six Extraction was born.
Pockets of an alien substance have been activated in America. This dark substance gradually spread out and covered the whole surface creating the Archaeans - humanoid monsters that are incredibly hostile. REACT division calls operatives on their side to fight back against this contagion.
The main goal of players is to examine the parasite, go on a raid, kill the Archaeans, collect data, and level up.
All progress in the game is tied solely to the experience earned, which opens up access to new locations, gadgets, operatives, and weapons for them. In addition, players have a base to customize guns and operatives' gadgets. By selecting one of them, the player goes to one of four locations, ranked by complexity: New York, San Francisco, Alaska, and Trout-or-Consequence. Respectively, the more complex the location, the more dangerous the Archaeans will encounter.
Each city has three maps, where players can enter randomly or choose a particular one. Each map is divided into three sectors with one mission per each. Complete all three missions, then evacuate and collect maximum scores.
The developers have come up with some interesting mechanics with the loss of a fighter. When you run out of health on a mission, your fighter doesn't die; they just get covered with protective foam. You can't use such fighters until you save them during one of the subsequent sorties on the same map by choosing someone else. After the rescue, the fighter will be unavailable for a while: they need to heal - just like the ones who managed to survive but suffered a lot of damage.
The more successful the sortie is, the more health will be replenished to the wounded. If you fail a rescue mission, part of your total experience and operative experience will be reduced, bringing you back. Along with the fact that you can't heal but only temporarily improve your health during operations, you rather quickly begin to value each soldier and avoid getting into the thick of it prematurely.
Archaeans don't have any very complicated and cunning tactics, they go back and forth until they spot you, then raise the alarm and run offensively. There are exploding Archaeans or large individuals with high health reserves, but the difficulty of dealing with them only comes down to their quantity and your life reserve. Even the most basic parasites take away a lot of your health in one hit, so the best tactic is to kill them from a distance.