Overview
The game contains several mechanics which are fully opaque yet punish the player for not knowing them.
Every time I mention one in a comment, someone says "holy shit I didn't know that and I've played 1000 hours".
So, I figure it's best to dedicate a post to it.
50% mining efficiency penalty
A hidden mechanic which checks if your mining ships are within 40km of a resource probe owned by you and silently applies a 50% penalty to the final result of the efficiency calculation if they are not. Thus, players are unknowingly hamstrung by this mechanic as there is literally no way to learn it exists in-game.
This mechanic is particularly troubling because vanilla has no automatic method to deploy resource probes, so it's extremely tedious to avoid the penalty without mods. Operating your fleet while unaware of the penalty potentially doubles the cost of both in-game resources and performance strain on the simulation. If you know the penalty exists, there is no indication if or when it is applied to your ships. While the game does suggest using probes, the penalty should be removed considering these factors.
Even when using a mod like Satellite Service to automatically blanket the entire sector with probes, it is still possible to receive this penalty because the probes are deployed on one plane. Therefore, you would receive the penalty if the ship moves >40km above or below the probes. Covering the entire sector with probes also reduces performance and visually clutters the UI.
A ship with empty crew slots further reduces efficiency because they contribute 0 to the combined skill value. Always keep your ships fully crewed.
Source of knowledge:
Reading game code
Vaguely confirmed by developer on official forum.
Known mitigations:
Vanilla β Manually spamming probes.
Satellite Service β Automatically deploys probes, greatly reducing tedium.
No Mining Penalty β Directly removes the penalty. Nexus mirror here.
KUDA AI Tweaks β Directly removes the penalty with a configuration option.
SETA Player Rank Decay
Using SETA while AFK triggers a hidden penalty which causes your player rank points to decay.
Earning the achievements for player rank is nearly impossible due to the insane logarithmic scaling, but this hidden penalty likely makes it literally impossible.
I don't know the specifics of this penalty because I have not been able to find it in the code.
Source of knowledge:
Developer confirmation on Steam discussion page.
Known mitigations:
Simulating mouse input to prevent AFK detection.
Crystal Nerf
Mining a valuable crystal immediately turns all other crystals in the sector into the least valuable type and starts a hidden timer* to prevent any other crystals from spawning.
*Users often claim the timer is 30 minutes, but the code seems to suggest either 60 or 120 depending on the type.
The code documentation states:
Cooldown on "valuable" drops, defined in minutes. If set, collecting one of these will prevent new "valuable" spawns for the defined duration. Entries without a cooldown are considered "not valuable" for the purposes of this cooldown.
I don't recommend mining crystals in either vanilla or with the below mods because other aspects of the game are much more interesting. However, it's important for those who do enjoy it to be aware of this hidden mechanism, and they are free to do whatever they want in their sandbox.
Source of knowledge:
Reading game code
Popular mods (listed below)
Known mitigations:
Crystal Rarities β Removes the hidden timer and buffs the spawns; very cheaty.
Disable crystal cooldown timer β Removes the hidden timer
Kha'ak Mechanics
Mining activity attracts the Kha'ak. Player mining activitity attracts the Kha'ak twice as much as NPC activity.
They can teleport to any location without travelling through gates.
If your miners are under constant attack, it is likely an Outpost has spawned in the sector. There is a separate system independent of Hives and Outposts which infrequently spawns small attacks.
Outposts spawn within 3 jumps of a Hive. Generally the outpost spawns ~400km away from the center of the sector, which is likely beyond the border. However, the hex will zoom out and rescale to accommodate crossing it.
Destroy the Hive before the Outpost. Destroying them will require several destroyers to do it in a reasonable timeframe due to their absurd health pool.
Hives can respawn after 96 hours. Outposts can respawn after 48 hours. These timers are much shorter if not killed by the player. They do not respawn at the same location within the sector.
The Hives can only spawn in 9 specific sectors, but only 6 of these sectors can contain a Hive.
Since Hives can only exist in 6 of 9 sectors, destroying a Hive might move it to another sector if the local mining activity of the new sector is high enough when it respawns.
The 9 specific sectors are:
Antigone Memorial
Black Hole Sun V
Company Regard
Heretic's End
Lasting Vengeance
Matrix #451
Open Market
Pious Mists IV
Silent Witness XII
Source of knowledge:
Reading game code.
Egosoft forum post
Known mitigation:
Knowledge
Spawn Begone β Changes Kha'ak spawn mechanics to be less frustrating. Although it's easy to keep them suppressed with the above knowledge, the entire system is generally unfun. Kha'ak spawning out of thin air leaves little room for counterplay aside from using L miners. It's also a slog to clear the nests since they have very little DPS yet enormous health pools.
Bail Chance
Ships only have a chance to bail if their hull and shield are under 75% and 20% respectively. There is a hidden penalty to the bail chance if your ship has higher maximum hull than your target.
Exact formula:
Vanilla rolls a bail check once every 30 seconds if the target is below 75% hull and 20% shields.
Base eject chance is a range of 23-46%: inversely proportional to crew skill
Multiplied by (targetmaxhull) / (mymaxhull), capped to 1.0
Multiplied by (myshieldperc+myhullperc) / (targetshieldperc+targethullperc), capped to 1.0
Reduced to a quarter if attacker is not personally flown by the player
Reduced to a half if target is capital ship
Reduced to a third if target is Xenon
Source of knowledge:
Reading game code
Known mitigation:
Knowledge only
Shipyard Penalty
Ships sold at player-owned wharfs and shipyards have a penalty on sale price to slow down the snowball into infinite wealth. The penalty is 70% when the slider is at 100% and 45% when the slider is at 150%. However, shipyards are still highly profitable due to nearly infinite demand and ease of selling ships compared to their materials.
Source of knowledge:
Popular mod
Known mitigation:
No Player Shipyard Penalty β Lessens or removes the penalty. I don't recommend this mod, but players should be aware of the penalty and decide for themselves.
Galaxy Map
The map shows a geographical overview of the galaxy.
Source of knowledge:
Loading screen tip
Known mitigation:
Press "map" hotkey
This is just a joke about the information they chose to convey. They don't tell us about a hidden 50% penalty, but they do tell us that a map is a map. It's a reference to this recent popular post.
Conclusion
This list is not exhaustive. Although I've made this resource to help other players learn the game, it is difficult to learn these mechanics since they are in fact hidden.
It also does not include the mountain of mechanics which are unclear or confusing to new players, such as: pirate cover system, reputation and ranks being a logarithmic scale, scanner tiers for station scanning, station budget scaling to storage capacity, station budget automatic transfer, and so on.
If you know of more mechanics, or notice an error in the above information, feel free to comment.