The Alien Ruins are vast, underwater complexes that the player can encounter in Barotrauma. They are most commonly found embedded into rocks and ice underwater, sometimes spawning as mission locations in Salvaging an Artifact missions. Exploring the Alien Ruins will often yield one or more Alien Artifacts, exotic alien materials or even powerful Alien Weaponry.
Alien Ruins are characterised by their sturdy walls, massive rooms, and the absence of ladders or stairs in vertical passages. However, the doors and the corridors connecting the rooms are slightly smaller in size than a regular human. These ruins are sometimes inhabited by Fractal Guardians as well as other creatures including Crawlers, Mudraptors and even Husks, which can be a considerable threat to an unprepared player. Proper weaponry and medical supplies are recommended when exploring a ruin.
Rooms and corridors in the ruins sometimes contain alien contraptions, most acting as obstacles which player must work around if they wish to explore the ruins to full extent. Notably, alien devices do not have conventional wiring, so attempting to make a submarine out of alien parts only is all but futile.
The motion sensor is the main trigger for the majority of traps in Alien Ruins. It has the visual appearance of a small white spherical installation, resembling a facetted eye with a slightly larger round "pupil" in the middle, connected to a blinking red light. When the player moves within proximity, the sensor detects the movement, which is indicated by the red light switching off and the "eye" spinning around rapidly with the "pupil" leaning sideways.
Motion Activated Electric Coil
The most common obstacle in alien ruins, this trap is composed of one or more motion sensors linked to a large alien electric coil, powered by an Alien Power Generator. Triggering the sensors would cause the walls of the room to be electrified, stunning and inflicting heavy burns on unfortunate divers within. Remaining in proximity of motion sensors will cause the coil to emit a constant shock, which could ultimately result in asphyxiation and death of the divers. Arrays of motion detectors can sometimes be found guarding a relic holder.
Motion Activated Turret
This trap features a motion sensor activated turret powered by an Alien Power Generator. When the motion sensor is tripped, the turret starts periodically scanning the room, firing at any moving target it comes across. If the player triggers the turret, they can sneak past it by remaining still while the turret light illuminates them.
This obstacle features a set of doors locked by a simple puzzle. The puzzle is composed of three buttons in a line. Each button have an Alien Light above it, and each light corresponds to a door. Pressing a button will toggle the state of lights directly above, as well as the state of other lights adjacent to it, which reflects the state of the doors. Turing on all three lights will open all three doors.
This lock is composed of two Alien Lights and a button. One of the lights periodically switches on and off. When the button is pressed while the light is turned on, the second light is lit and the door opens.
A round generator with a blue hue, presumed to be the power supply for other alien contraptions, contains a single Alien Power Cell. Removing the cell will cut off the power supply to nearby Alien devices, though deactivated Alien Coils would still contain enough charge for a brief shock.
The alien pump can be sometimes found in rooms connected to an empty alien generator. The player can insert a power cell into the generator to power up the pump. The player can then toggle the state of the pump by pressing a button next to the installation, which pumps water into the room by default. When the light above the button is off, the pump will flood the room. While the light is on, the pump drains water from the room at an incredible rate, capable of emptying a large room in very little time. However, as Alien ruins contain no ladders and the only way to access rooms above is by swimming, players might be discouraged from pumping out the water.
Exotic alien curios are the main incentive for players to explore ruins they come across. However, there is no guarantee to the yield of each ruin.
Artifacts is the term given to a series of relics left behind by extraterrestrials on Europa. They are frequent targets of salvage missions in Quest Mode, and are potential sources of rare raw materials. Both the origin of these artifacts and their purpose is unknown.
Each artifact tends to have dangerous effects on their environment; for lack of understanding, they are impossible to prevent and can only be worked around. It is unknown how much of it comes from their intended function, normal side-effect of their working, or degradation sustained due to a lack of upkeep.
Amongst the alien ruins, the player can find various other items inside Small Alien Chests and Large Alien Chests.
- The Alien Power Cell is used to power Alien Weapons and Alien Generators.
- The Alien Pistol is a ranged weapon that deals Burn Damage and inflicts Psychosis.
- The Ancient Weapon is a ranged weapon that deals Burn Damage and high damage to structures.
- The Alien Flare is a bright and long burning Flare item.
- The Alien Trinket is a minor artifact that deconstructs into an Oxygenite Shard.
- The Alien Curio is a minor artifact that deconstructs into a Sulphurite Shard.
- The Alien Ornament is a minor artifact that deconstructs into a Physicorium Bar. Rather uniquely, it gives off the same proximity sound effect as an alien artifact .
- Every generated level in Barotrauma contains an artifact somewhere, even if only laying on the cavern floors. This implies their creators must have been incredibly prevalent in this section of Europa.
- As of Version 0.8.2.0, items taken from the ruins in Campaign mode will now be present in the next round. Previously, these items were deleted after ending the round.
- Before Thunder Under the Ice update was released, players were unable to cut open Alien Doors with a Plasma Cutter and had to use a Crowbar to force the doors open instead.
- Contrary to popular belief, the relic holder does not negate the various disruptive effects caused by Alien Artifacts. This is most easily seen as Faraday Alien Artifacts still emit EMP shocks (and corresponding visual effects) when they are in relic holders. In addition, Thermal Alien Artifacts have been observed to set themselves ablaze while still remaining inside relic holders in ruins.
- As ruin walls use the same internal file structure as submarine walls, most third party anti-griefing systems will return a false positive whenever they are damaged. This could be intentional, as it is possible to construct a submarine out of ruin walls in the Submarine Editor.