Alien Swarm

Alien Swarm is a multiplayer top-down shooter video game developed by Valve. It is a remake of a mod for Unreal Tournament 2004, and it was developed by the original team, who were hired by Valve during the course of the development process.

Gameplay

Alien Swarm is a top-down shooter, where four players can join a single co-operative game, the aim of which is to progress through science fiction-themed levels while eliminating waves of aliens. Players can choose from 40 different pieces of equipment, ranging from weapons like assault rifles to grenade launchers and offhand items like mines and healing beacons. The game includes persistent statistics, unlockable equipment, and achievements.

The game is class-based, with players choosing from the roles of Officer, Special Weapons, Medic, and Tech. Each class has two selectable characters, differentiated by their abilities.

Before the mission, players can change their character's loadouts and offhand items. After each mission, experience points are gained. While leveling up, the players will unlock new weapons and items to use. The mission involves the team advancing in the same general direction, often with multiple objectives to accomplish. As they advance through the level, they will find certain key points blocking the progress, which are cleared through a variety of methods, from welding to shooting to hacking. Meanwhile, many aliens (known as Swarm) will attack the players from all sides. Swarm can spawn unpredictably, and will often attack the players with mobs of enemies, as described by their name. There are many different types of Swarm, with different behaviors and attack patterns. Players can fight Swarm using many tools, including weapons, explosives, or using environmental hazards (e.g. explosive barrels).