Strategy - Tactics - Artificial Intelligence

The most important part of Terran Shield is its strategy core component. We are striving to provide the best in the game’s other areas (graphics, sound, effects and animation), but the strategy and tactics shall remain our main focus.

The other core goal of our philosophy is to provide the player with the freedom to express themselves within the game: the freedom to play according to their own unique style and not get penalized by the game as a result of that. 

On the AI perspective, here will be no overall strategy or tactic that the computer will be unable to handle. The player has to be inventive and at the same time reactive at the AI moves and type of play.

The current Terran Shield AI is a combination of a Utility AI and a Behavior Tree AI called “The Six Headed Hydra” because it has a head for each alien leader. The  structure reveals three branches, each with its specific function. The first is the “Analyst” which analyzes the player’s playstyle and generates some variables that the main AI body structure “ The Master” uses to favor certain response on the Geoscape strategy level. The response is handled by the other AI structure called “The Executor”.

The Executor is the one responsible for the tactical map decisions and plans, in line with the variables that The Master sends before a mission. The Six Headed Hydra is in its incipient phase, but is already doing fine in our alpha demo and that thing makes us optimistic about the full implementation of the AI in the final game.

One of the new features that we have reserved for the aliens is their internal game mechanic. In order to construct bases, ships, weapons and breed more combatants, the aliens need to harvest resources. They obtain them from the ocean bed, but also from the surface where they use the hit, steal and run tactic. They harvest: oil, metals, radioactive materials and organic material usually from the oceans (fish and plankton). Any development plan the AI will implement for the aliens include a combination of these harvested resources and if the player restricts the quantity for some of those resources, the AI will adjust the development plan accordingly.

For example, if the player hunts down the harvester crafts that gather metals and oil, the aliens will construct more breeding oriented bases and will try to overwhelm the player with large numbers of soldiers in the tactical fights, as well as smaller fighting crafts but in larger number on the Geoscape.

Here are some strategic and tactic examples, to indicate how challenging the AI can be during the game when playing in the “Impossible” game mode (Superhuman):

Strategic situation 01: 

 Aliens' underwater harvesting sites

 New Terran Shield underwater bases


 Aliens' underwater bases

 Terran Shield underwater bases

The first situation shows the AI on the left with the pentagon shape bases and the player on the right. The player strategic style is an aggressive-offensive one. Typically this type of play style, combined with the save/load option is very difficult for the AI to handle in any game. 

Initially, the player expands near the harvesting sites of the aliens in the Atlantic Ocean. Bear in mind that the Terran Shield strategic Geoscape is a field in which the AI and the human player meet almost like on an RTS pvp map, similar to Starcraft. They have a main base from which they expand, gather resources or attack with rushes or all-ins, if they want. The only real difference is that the alien/AI starts with 5 bases and a lot more resources and troops than the “poor“ player, who has only one land base and one underwater base. The player is not so poor in fact, because he has on his side hundreds of thousands of years of mind evolution from his ancestors. This is a lot of potential, that the AI doesn’t possess.

Strategic situation 02: 

 New Aliens' underwater bases


 Aliens' underwater bases

 Aliens' underwater harvesting sites

 Terran Shield underwater bases

Back to the strategic simulation, the AI will respond to the player’s aggressive move by placing its expansion bases far away from the player’s reach, in the Pacific Ocean. At the same time it will attempt to lure the player into a never-ending cat and mouse game near the harvesting sites in the Atlantic. It will fake the harvesting from those sites and at need, will sacrifice some UFOs with few members and loot to keep the player busy in that area, while it finds new harvesting sites and develops its bases and tech in the Pacific area.

The player will have few resources to collect from UFO recovery missions and they will slowly develop and upgrade their bases. The AI will be miles ahead by the time the player will have enough money to expand into the Pacific area. This doesn’t mean that the aggressive play style doesn’t have good odds for success, it only shows the AI’s reactive style of play, to counter the player’s style.

The aggressive style of play must be backed up by scouting and planning in order to be successful, because you can’t win the game with pure rush play style. An attack early in game at the aliens' bases is out of the question, regardless of difficulty or the player’s skill and experience, as any veteran TBS game player knows.


Let see now some of the AI moves on the tactical level. Similar to strategical level AI, the tactical AI will develop special tactics and play style that will force the human player to play at his best.

Symbols of Tactical battle simulation

 the Squid

 alien small fighter ship

 human aquanaut

 alien squad leader

 alien Frogman

 various alien types

 dead alien

 jellyfish sentry (alien)

 dead jellyfish sentry (alien)

 movement direction

 non-lethal weapon shooting direction

 lethal weapon shooting direction

 visibility range

 explosive weapon effect area

 gel gun weapon ensnare area 



Turn 01-03:
Tactical battle simulation, without the squad leader

(conditions: day, 30m deep, water 15OC, no currents, dunes and algae, visibility range:~20m)

- humans exit The Squid and spread near the deploy location;

- aliens are spread around the UFO and wait for a sign of human intrusion;

- humans approach the center of the map and are spotted by an alien, right at the end of aliens' turn;

- aliens that are near the spotting zone retreat and take defensive stances, partially burying themselves under the sand.

Turn 04 (aliens): 
Tactical battle simulation, without the squad leader

- aliens approach the conflict zone and take defensive stances; one of the aliens shoots with a torpedo launcher, but misses;

- another alien shoots with the gel gun and slows the humans; meanwhile, other two are trying to escape;

- but it is too late, the "key alien" from the UFO has already left the ship to search for a hiding spot.

Turn 04 (humans): 
Tactical battle simulation, without the squad leader

- humans continue their approach and get a reaction shot from one of the aliens;

- the player reloads the game and sends a group of soldiers at 5’o clock for a flank attack;

- the two aliens sighted were taken out by human sonic guns.

Turn 05 (humans):
Tactical battle simulation, without the squad leader

- humans take out the remaining aliens, one by one;

- the aliens react, but their reaction shot is deflected by the human armor;

- the battle is won!

We can see that the aliens without a leader will fight an “everybody for themselves” type of battle and don’t have a clear tactical plan.

Let see now how the mission would look like with a squad leader in the aliens' ranks.

Turn 01: 
Tactical battle simulation, with the squad leader

(conditions: day, 30m deep, water 150C, no currents, dunes and algae, visibility range:~20m)

- humans exit The Squid and spread near the deploy location;

- aliens are spread around the UFO and wait for a sign of human intrusion;

- their squad leader launches a scouting ball that opens and spits out 3 jellyfish scouts.

Turn 02: 
Tactical battle simulation, with the squad leader

- humans approach the center of the map; the squad leader launches another scouting ball, two of the earlier jellyfish spot the 12-human formation;

- the AI decides to play evasive and issues orders of retreat because the odds of winning against such a large human force are low for the aliens.

Turn 03: 
Tactical battle simulation, with the squad leader

- humans advance and shoot towards two of the jellyfish scouts; due to their transparency, getting a direct shot is difficult, so the human has to shoot with all his aquanauts; even so, one of the jellyfish scouts survives;

- two of the aliens placed outside of the UFO shoot with the gel gun and create a gel barrier near the UFO;

- the other 3 jellyfish scouts are placed in the center to spy the human’s movements.

Turn 04-05: 
Tactical battle simulation, with the squad leader

- 3 aliens position themselves near the entrance of the UFO and shoot with torpedoes when
the humans try to bypass the gel area; 

- some human soldiers are hit, forcing a reload from the player; they are repositioned outside the torpedo blast area;

- the 3 aliens who shoot the mortars, retreat inside the UFO;

- the squad leader gives the final evacuation order and the UFO flees;

- the battle is undecided!

With the squad leader on the field, the aliens not only behave more coherently, but also manage to escape and flee with their UFO.

If the aliens had had a larger force, at least 1/4 more than the humans, the battle scheme would have been different. They would have held the line behind the gel areas and would have forced the humans to do flanking maneuvers, or forced their advance with a lot of torpedoes and crab bombs. 

A proper tactic from a veteran player would have been to put in front only a small force to be spotted by the scout jellyfish and at the same time he would have tried to flank the aliens from the beginning, so the AI wouldn’t have the time to put its escape plan in motion.


Will see in the future demo missions how the AI will try to make the player’s life hard, always keeping an ace up its sleeve, to surprise and confuse the player.

But more on AI, strategy and combat tactics, will follow as the game develops and we will have some in game demonstration from the alpha game version.

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