Leaderboards

Several **leaderboards** are tracked in *Subterrain*: "Shortest Purification Time", "Shortest Escape Time", and "Longest Survival Time". Each of these categories is further split by the difficulty that the player plays on. Thus, for example, Shortest Escape Time on Hardcore is distinct from Shortest Escape Time on Easy. This results in 12 different leaderboards available. It should be noted that playing on a higher difficulty only qualifies a player for that difficulty and no others; so, for example, playing on Hardcore will only place you on the Hardcore leaderboards, and you will not be placed on the Normal or Easy leaderboards.

If the player uses cheat commands, both leaderboards and achievements will no longer be updated for that save file; an entirely new file must be started. Permadeath is not recorded on the leaderboards at all, so it is not recommended at all for any leaderboards attempts, *especially* for Longest Survival Time save files.

## Shortest Purification Time

This leaderboard requires the player to defeat the final boss. Siding with them is not sufficient to place on this leaderboard. This leaderboard can be perceived as a traditional speedrun - that is, complete the game's main objectives as fast as possible.

Reaching the final fight has the following requirements and prerequisites:

* 15 Purification Filters and Regulators
	+ Level 3 Software for all facilities (too many level 3 materials than can realistically be found)
		- Level 2 Research and Engineering Software
	+ Complete Escape Sequence
		- Navigation Module, 5 Space Shuttle Fuel, and IEVA Suit
			* Level 2 and 3 materials, as well as level 2 Research and Engineering
	+ Enough power to comfortably keep the whole colony powered~

While completing these requirements, the player should not neglect researching necessary combat items. Focus on whatever combat items make the fight the fastest for you (ease is less of a factor, since you can technically try the fights until you are satisfied).

~ While it is theoretically possible to fulfill all of the requirements and reach the fight with only one reactor module installed, it is excessively unlikely and impractical.

## Shortest Escape Time

This leaderboard requires the player to begin the escape sequence using Shuttle 2. This is likely a relic from *Subterrain's* beta, when the purification portion of the game did not exist yet.

Beginning the escape has the following requirements and prerequisites:

* Navigation Module, 5 Space Shuttle Fuel
	+ Level 2 and 3 materials, as well as level 2 Research and Engineering

The IEVA Suit is not required, since it only allows survival for the period after the crash, which is not required by the leaderboard. The level 3 materials requirement for the Navigation Module can be satisfied by looting corresponding jewelry while you're looking for the software chips. However, it is unlikely that you can avoid the level 3 Biosphere chip for the Shuttle Fuel, since 150 of each material is required and miscellaneous items that produce Biosphere materials are much less common.

## Longest Survival Time

This leaderboard simply measures how long the player survives on the colony for. While this may sound daunting when you realize that the core materials (metal composite, glass fiber, and electronic resin are non-renewable, it is theoretically possible to survive indefinitely.

Once the player has completed their equipment and research, very little in terms of resources are actually required. Guns, melee weapons, and suits can be repaired with no material cost (grenades should be avoided/minimized, since they require non-renewable materials). Reactor modules can be repaired with no material cost, and MK IVs can easily maintain the entire colony at their repair values. Oxygen, thermals, and power are available at Central Control with no material cost. At this point, only West's physical needs must be considered, and fatigue can be ignored since it only requires a bed (which do not require maintenance of any kind).

Thus, only West's hunger and thirst need to be considered. Although safe foods and drinks are indeed limited, the Biosphere can produce foods that sate both hunger and thirst, while requiring no material input (tomatoes or lemons are best for this purpose, or corn if hunger becomes a much bigger issue). This removes the worry of hunger and thirst, but then makes contamination a concern, since consuming Biosphere products is guaranteed to contaminate West. Fortunately, decontamination pills only require blood extract (an enemy drop) and Biosphere products in order to be produced; none of the non-renewable materials are required.

Since all decontamination pills require exactly 50 blood extract, and Biosphere products should be plentiful at this point, it is most effective to produce Decontamination Pill A, since its quicker effect gives the contamination less time to reproduce, as well as allowing you to use another pill sooner. Since blood extract is only available from killing enemies, the player must keep at least one area impure so that they keep spawning. (If an area is already purified, enemies will start spawning again if the area's power is turned off. Removing the purification equipment does **not** allow them to spawn, if the area is purified.) Core areas, such as Nilson Engineering, are recommended, since their smaller layouts allow for a higher density of enemies. Global Infection should also be kept below 25% to prevent mutant invasions (unless they're desired, in which case keep it above 25%). At this point, the only threats are dying to enemies (or self-damage) and accumulating too much contamination without decontamination pills available (although this is a slower killer, so there is time to recover).

The contamination from Biosphere foods is more severe on higher difficulties (15 on Nightmare, 10 on Hardcore), so pills must be managed carefully.

1. ↑ https://steamcommunity.com/app/340490/discussions/4/359543542234569784/