(i'm not sure why these map icons keep disappearing over time)

Hitpoints (HP):
The amount of damage the unit can take before it dies. Indicated by a green bar when a unit is selected.

Endurance:
Indicated by a blue bar when a unit is selected. Some creatures possess special abilities that drain endurance when used. When the endurance bar is empty, the unit cannot use its abilities. Endurance regenerates over time. Note that not all creatures will possess an endurance meter.

Defense:
The percent of incoming damage absorbed by the unit; e.g. a creature with 60 points of defense will only receive 40% damage from standard attacks. The maximum amount of defense a unit may possess is 60.

Effective HP (EHP):
The number of hitpoints the unit has after its defense rating has been factored in.
EHP can be calculated with the following formula:

HP / [1 - (defense / 100)]

For example, a creature with 250 HP and 30 defense will have 357 EHP.
• 30 defense / 100 = 0.3
• 1 - 0.3 = 0.7
• 250 HP / 0.7 = 357 EHP.

Power:
Power is a hidden stat that determines a unit's final research level, taking into account its total damage, hitpoints, and defense (armor) ratings. The power equation as of Tellurian 2.6.1 is as follows:

(((h/(1-a))^(0.608))*((0.22*d) + 2.8))

The power thresholds for each level:

rank2pow = 60;
rank3pow = 120;
rank4pow = 230;
rank5pow = 400;

It's important to note that high power units will be more expensive than low power units of the next highest research level. A level 3 creature with 229 power will cost more than a level 4 with 230 power, for instance.

Game Ticks:
You will occasionally see references to "ticks" later on in this guide. A tick is a unit of time roughly equivalent to one tenth of a second.

Assassinate:
Endurance cost: 100
Attack damage done by the assassination attempt is 45% of the victims maximum HP.

Barrier Destroy:
Passive effect:
50% damage multiplier against structures.
Ignores damage taken from bramble fences.

Camouflage:
The creature is undetectable by enemy units until it attacks or is attacked. Once disengaged, the creature will cloak itself again after 10 seconds. This ability is countered by Keen Sense, Sonar Pulse and Sounbeam/Anti-Air Towers.

Charge Attack:
Once in sight, the creature will quickly and relentlessly chase down its target to get the first attack. The initial attack receives a 100% damage boost. While charging, the creatures speed is double.

Colony/Conglomerate:
Units with these abilities will only take up half the population space they'd usually do (rounded up). Both abilities are identical, differentiated only by their associated body parts. Colony is on the head, while Conglomerate is on the torso.

Defensive Cloud (Stink Cloud):
Endurance cost: 80
The unit emits a defensive cloud which slows all enemy units within the cloud down to 20%. Units with the Immunity/High Endurance abilities receive no speed penalty.
The duration of the cloud is dependent upon creature rank:
• Rank I: around 6 seconds
• Rank II: around 8 seconds
• Rank III: around 10 seconds
• Rank IV: around 12 seconds
• Rank V: around 14 seconds

Defile Land:
Endurance cost: 35
The creature emits a foul substance that covers the terrain, slowing and damaging any enemy units caught within. Affected units lose roughly 2% of their total HP per second, and receive a 70% speed penalty. The defiled land is visible only to the caster and units with the Keen Sense and Sonar Pulse abilities. Countered by Immunity. This ability affects allied units.

Deflection Armour:
Units with this ability have a 20% chance on deflecting ranged attacks back at their opponents.

Digging:
The creature can burrow underground. While underground the following modifiers are applied:
• 20% speed boost
• 50% less damage taken
• 50% reduction to endurance regeneration rate
• 80% sight radius reduction

Disorienting Barbs:
This ability negates the attack and defense bonuses granted by Pack Hunter and Herding, respectively.

Electric Burst:
Endurance cost: 100
The unit briefly emits a powerful electric field, damaging any units caught within its radius.
The damage dealt by the burst is dependent upon the creature's rank:
• Rank2= 60
• Rank3= 102
• Rank4= 135
• Rank5= 200

Flash:
Endurance cost: 80
The creature emits a bright flash of light, disabling ranged attacks and reducing the sight radius of all units within its radius for a short period. This ability also affects allied units.

Frenzy:
Endurance cost: 22.5
The creature receives a 50% bonus to its damage and speed, but in return receives 30% more damage from incoming attacks.

Herding:
Passive effect:
Gives a 30% defense increase when a total of 4 or more creatures of the same type are within 20 meters from each other.

High Endurance:
• Normal endurance regeneration rate: 2/second
• High endurance regeneration rate: 5/second
High endurance also negates movement penalties from Stink cload, poison, sonic attacks, soundbeam towers.

Horns:
This ability reduces the opposing creature's defense rating by 35%, making it very effective against high defense, as well as units with the Herding ability.

Hovering:
Endurance cost: 75
Creature can fly over/on cliffs.
Max hover distance: 200meter
-50% speed while hovering
Can't attack/ relocate selected landing location.
While hovering creatures can be hit by anti-air towers.

Immunity:
This ability renders the unit immune to chemical-based abilities, such as Poison, Plague, and Defile Land. It also negates the slow-down effect from Stink Cloud (ranged attacks will still be disabled, however).

Infestation:
The creature can sacrifice itself to infest an enemy structure, doing a set amount of damage over a period of time. Once inside the structure, the unit will do 1500 damage over a period of 375 ticks. The unit cannot be recovered.

Keen Sense:
The unit can detect digging and camouflaged units within its sight radius.

Leap Attack:
The creature will quickly rush in to get the first attack when in close quarters. The initial attack will receive a 50% damage boost.

Overpopulation:
Passive effect:
Units with this ability receive a 50% reduction to build time.

Pack Hunter:
Passive effect:
Gives a 30% damage increase when a total of 4 or more creatures of the same type are within 20 meters from each other.

Perforate:
This ability reduces the opposing creature's defense rating by 35%, making it very effective against high defense, as well as units with the Herding ability.

Plague:
Endurance cost: 100
Damage the plague does per second, per attacker rank
Rank1= 3/s
Rank2= 3/s
Rank3= 6/s
Rank4= 9/s
Rank5= 12/s

Plague lasts for 15 seconds.

A plagued entity's plague spread search radius is 20meter.
(plague will transfer every 3seconds)

Poison:
Poison lasts 10 seconds, this timer can be renewed with new attacks.
The amount of damage the Poison deals per rank.
• Rank III: 20
• Rank IV: 25
• Rank V: 50
Creatures effected by poison get a 25% speed penalty.
Creatures effected by poison deal 15% less damage.
These values count for the following abilities:
Poison Bite, Poison Sting, Poison Tip and Poison Touch

Poison inflicted with ranged attacks deal the same amount of damage at every rank and have no speed/damage modifier.
• Rank III: 25
• Rank IV: 25
• Rank V: 25

Quill Burst:
Endurance cost: 60
The creature releases a number of sharp quills in all directions, damaging any units caught with the burst's radius.

Damage is dependent upon creature rank:
• Rank I: 8/tick
• Rank II: 10/tick
• Rank III: 12/tick
• Rank IV: 15/tick
• Rank V: 20/tick

Regeneration:
The creature regenerates a set number of hitpoints per second, determined by its rank.
• Rank I: 0.25/s
• Rank II: 0.75/s
• Rank III: 1.25/s
• Rank IV: 1.75/s
• Rank V: 2.0/s

Loner:

The radius at which the loner bonus becomes active is 30 meters.
Loner Speed bonus: 50%.
Loner Sight Radius bonus: 50%.

Damage bonus multipliers:
Artillery ranged bonus per creature rank:
• BonusRank2: 300%
• BonusRank3: 300%
• BonusRank4: 400%
• BonusRank5: 500%

Direct ranged bonus per creature rank:
• BonusRank2: 400%
• BonusRank3: 400%
• BonusRank4: 500%
• BonusRank5: 600%

Melee bonus per creature rank:
• BonusRank2: 300%
• BonusRank3: 300%
• BonusRank4: 400%
• BonusRank5: 500%

Damage reduction per creature size:
• ReductionSize1: 10%
• ReductionSize2: 10%
• ReductionSize3: 10%
• ReductionSize4: 20%
• ReductionSize5: 20%
• ReductionSize6: 30%
• ReductionSize7: 30%
• ReductionSize8: 40%
• ReductionSize9: 50%
• ReductionSize10: 60%
• ReductionSize11: 60%
• ReductionSize12: 60%

Damage reduction per creature rank:
• ReductionRank5: 25%

Build speed modifier per creature rank: (multiplies to base ticks)
• SpeedRank2: 200%
• SpeedRank3: 200%
• SpeedRank4: 200%
• SpeedRank5: 200%

Sonar Pulse:
Endurance cost: 100
The creature may reveal a portion of the map (100m radius) for an extended period of time. Use of this ability is indicated to all players via a green particle effect onscreen. This means enemies will know when you're watching them, so use with caution.

Web Throw:
Endurance cost: 100
The creature can use its natural web-spinning ability to ensnare opponents in a sticky web, immobilizing them for a short period of time.

As of now there's no official campaign available, nor are there any plans for making one.
However, an unofficial Tellurian campaign can be found here.

Add-ons:

AI Fast L3:
The AI will make reaching level 3 quickly its primary goal for the early game.

AI L2 Rush:
The AI will tech to level 2 quickly and engage the player aggressively.

AI Proxy Rush:
The AI will attempt to surprise the player with a level 2 rush from a forward Creature Chamber built near the player's base.

AI Reduced Resources:
Hard and Expert difficulties receive a nerf to their respective resource bonuses.

AI Slow L2:
The AI will research level 2 slowly, focusing on economy over combat. Not recommended for 1v1s.

AI No Tactics:
The AI will not perform any of the tactics described above.

Enable Minilabs:
Enables the player to construct the "Minilab" from Creature Chaos. Minilabs can produce henchmen, as well as ground and amphibious units. This structure replaces the Air Chamber; flying units may now be built from Creature Chambers and Water Chambers instead.

Increased Resources:
Significantly increases the amount of coal per pile.

Standard Population Calculator:
All creatures take up 1 pop space, regardless of their power rating.

AI Player Info:

Coal bonus multipliers:
DifficultyEasy: -25%
DifficultyNormal: none
DifficultyHard = +30%
DifficultyExpert: +75%

Electricity bonus multipliers:
DifficultyEasy: -25%
DifficultyNormal: none
DifficultyHard = +20%
DifficultyExpert: +50%

Starting Resources:

Standard:
Coal: 500
Electricity: 100

Quick Start:
Coal: 1500
Electricity: 500

Resource conversion:

20% of Coal to electricity or electricity to coal will be lost.

Donations:

10% of resources donated will be lost.

The amount of resources lost upon destroying your own structures is 15%.