The third millennium of Earth came with an age of technological and social revolution after thousands of years of warfare before humanity finally found peace. In this climate of progress, Metropolises emerged from the various cities before eventually linking together, transforming the Earth into a vast hive of human activity as nature was driven out. This golden age of progress however was marred by overpopulation, and so millions of scientists desperately sought a solution to this problem.
The scientists eventually discovered that the star system Proxima Centauri contained a habitable planet but was unreachable due to mankind having no form of FTL. In a flash of insight, one "Dr. Emily Nagome" found out how to break the constraining three dimensions of our world by accessing a fourth dimension in which movement can cross great distances whilst taking place outside the flow of normal time. This was all mankind needed before realising their manifest destiny, going forth into the great unknown whilst colonizing worlds in their wake. Mankind also made their first contacts with various aliens, some friends whilst others enemies. As man forged a great empire, its vast wealth would eventually lead to the foundation of "Centronom" which would later become the new capital world of humanity. Earth however would be stripped of its cities as painstaking natural and ecological reclamation projects aimed to restore Earth as a symbol of man's ancestral homeworld. Earth became a paradise, pilgrimage planet that also served as a research hub on expanding the farthest bounds of technology.
Faced with the challenges this galaxy presented, humanity created countless innovations from nanites that sustained development on harsh worlds to the first true androids that could look and act like humans. Acting as protectors of man they were first deployed on Centronom, however a freak accident in their coding caused them to go insane, the most notable incident being one android pilot crashing his ship into the space station holding the 5th Congress of the Imperial Senate, killing everyone aboard. This and other related deaths led to the outlawing of all android research and production.
In 3226, mankind's galaxy spanning empire buckled under social strain. Unable to cope with such rapid expansion, the empire fractured as warring factions ended this peaceful age as they began to divide up and fight over vast regions of space. Sensing weakness, expansionist aliens started probing humanity's borders whilst the desperate admiralty of the old empire decides to use its "secret weapon" to alter its downward spiral.
Dante, a young, loyal and eager Lieutenant is called by his commanding Colonel who proceeds to instruct him that the planet Achilles has been under subsequent anarchy and war for some time now. The Colonel subsequently gives him the task that he has to restore order to the sector. Upon doing so, Dante is ordered to expand control over the cluster of worlds under his command by dealing with pirate fleets. Eventually Dante is instructed to rendezvous with an Admiral Mark Tullen, whose flagship Thorin
is under attack from Garthog forces and must withdraw. After Dante successfully intervenes, he is promoted to Captain.
Dante is then introduced to the neighboring Garthog empire, whose forces make periodic attacks upon Galactic Empire worlds and so Dante must fend them off. At the same time of repulsing Garthog incursions he also has to deal with a particular virulent virus that requires quarantine of the planet New Caroline. Upon defeating the infection and reporting viral developments to the Colonel, he suspects biological warfare and sends up for some specialized equipment to detect virus carriers whilst Dante is recalled to escort the Admiral's fleet to New Caroline. Soon the Garthogs ambush the fleet, and shortly after the Garthogs are repulsed another viral outbreak occurs. The sensor equipment confirms that it is the Garthogs who are engaging in viral warfare, and swiftly dealing with the infection and the viral transport ships, they are dissuaded from making the same attack again.
Dante begins to have recurring flashbacks whilst he develops suspicions that Catherine Reinhardt, the ship's doctor, may be an enemy spy. After rigging up a camera feed in his quarters, his suspicions are correct in that the doctor is secretly accessing his room and his computer for unspecified reasons. Dante reports this to the Colonel who states that he will take a look into this matter. Later, Dante is assigned to protect a money transport from Garthog pirates and then to retrieve a prototype destroyer stolen by the Garthogs which upon its recovery, Dante is promoted to Commander.
The Colonel then orders Dante to deal with the renegade governor of the planet Zeuson by blockading it. After the governor is dealt with, Dante must escort a cargo vessel as well as taking the fight to the Garthogs. After the Garthog empire has been fully conquered, Dante is promoted to Admiral and given the command of the Thorin
. Suffering from more intense flashbacks he goes to the new ship's doctor with inquiries into robotics, who tells him about a " Professor Reinhardt"'s "infernal android project". After sending his suspicions to Earth, Dante tracks down Professor Reinhardt who reveals that Dante is in fact, the "secret weapon" of the empire. Dante is an android whose entire life, family and friends were fabricated to make him identify with the image of a young, ambitious officer. He was created after long range probes detected the coming of an expansionary alien race invading the galaxy. It was the hope that Dante would be able to command the failing old empire to stand against this threat, and to restore it beset by hostile aliens and within the myriad of its own problems. He was designed to be the "perfect leader", one who had to manage the Galactic Empire on an exceptional level of technical, military and governing abilities. Catherine Reinhardt was the Professor's daughter, sent to keep an eye on Dante as the military desired more tests to assess Dante's mental stability. Professor Reinhardt then states that the future of mankind rests within Dante's hands.
Dante is promoted to Grand Admiral after encountering the alien race mentioned by Professor Reinhardt as it encroaches Galactic Empire fleets and worlds. These aliens are identified as the Dargslans, a warlike, conquering alien race bent on subjugation of all who stand in their way. When first encountered they are an extreme, growing militarist power utilising superior technology and as such Dante is drawn into a long war in the attempt to gain a technological and manufacturing equality with these aliens. After the Dargslans are defeated, various warring factions throughout the galaxy rally to the Galactic Empire after seeing this sign of strength, thus preventing a possible interstellar war. Historians disagree on what saved humanity, many believe that a higher power preserved what was gained in the last millennium whilst others argue that only a machine unswayed by doubts and fears saved mankind from annihilation. Only the admiralty knows the truth however, and the only declaration was that a secret weapon led to their triumph, what this may be however still is shrouded in mystery, secrecy and classified government files.
Imperium Galactica is set sometime during the fourth millennium with the player given the task of rebuilding the Galactic Empire. The player is placed into the role of a Lieutenant called Dante who is given a series of missions to complete. You then advance to the next rank upon completion of these missions which gives more strategic options and available ships to command. Being promoted also unlocks a greater section of your area of the galaxy to police, conquer and colonize. This continues until you reach the rank of Grand Admiral, where the game is now fully unlocked to the player. At this point, the whole map of the galaxy is available to be viewed and the event missions effectively cease.
When you are in command of a region, you must ensure that its economy and colonies are contributing to you in some way. You collect taxes, produce colonies, move your fleets, research and manufacture as game time passes which can be paused, sped up or slowed down. Events also happen based on specific in-game times. You must also ensure that the people are well-fed, happy and reproducing, whilst if the tax level is too high it causes a constant migration of citizens and eventual planetary revolts. Research into weapons technologies and such offers more competent ships whilst colony technologies offer more ground defense and morale boosting structures. 75 new scientific discoveries can be made over the course of the game, each requiring prerequisites of empire wide "development centres". Only one development centre can be sustained per planet, and the more advanced technologies may require a combination of five specific types of development centre throughout your empire. In addition, successful invasions can result in the chance of procuring colony technology from other races.
Your enemies are several alien races. They each have their own styles of architecture, ships, and unique land-based units. However, some are more inspired than others, and at the Grand Admiral stage diplomacy options ensure that all-out war is not the only way to victory. The list below details all of the races in the game:
- Galactic Empire, (a.k.a. Human Empire, "Old Empire"): The player's faction, which appears on the starmap as orange to the far middle left of the galaxy. The player does not initially have any access to special land units unlike the AI alien races however late in the tech tree the Behemoth tank used by other human races as a unique special can be unlocked.
- Alliance of Free Traders (AFT): "Once part of the Old Empire, the traders left to create a new empire for themselves. They are a peaceful race of traders and enjoy good relations with Ychoms." The AFT is a human offshoot race that utilises Behemoth tanks as their unique vehicles in battle.
- Dargslan Kingdom: "Very little is known about the Dargslans. Intelligence reports show that they have extremely powerful ground attack forces, as well as a competent space fleet." The Dargslans expand primarily by invasion rather than colonization. The Dargslan unique land units are "Auto-repair tanks". A distinct Dargslan ground advantage is one where they are able to make all of their ground forces appear in front of you at the start of a battle. Defeat of the Dargslans by having them surrender to you or by conquering every last one of their colonies ends the game and it is also possible to band other alien races against them.
- Dribs: "The Dribs are a proud race, with advanced knowledge of mechanics and architecture. They have known of the Dargslan race for a long time, since the Dargslans occupied some Drib territory." The Dribs use a special "Paralysis tank" in battle.
- Ecaleps : "With the rapid expansion of their empire, tax revenue has increased to a very high level. This partially explains their obsession with money.." The Ecaleps arm themselves with unique "Anti-missile tanks", which have an immunity to the player's Rocket Sled missiles.
- Free Nations Society (FNS): "Once part of the Old Empire, they declared themselves independent a long time ago. The Free Nations Society has developed rapidly, occupying territories with ease. The Society is well known for their arrogant attitude and contempt for the Empire." Another human offshoot, they also use Behemoth tanks.
- Garthogs: "The Garthogs are a contemptible and un-trustworthy race, who implant their young with bio-mechanical devices. They have a special interest in mechanics and are renowned for stealing the technology of other races. It is rumored that they destroyed an entire race, known as the Nubs, to obtain their secrets. The Garthog Empire is close to the Human Empire and there has been conflict for 10 years." The Garthogs bring their "Radar Jammer" vehicles into battle, which disables your battle radar on colony fights.
- Morgarths: "The Morgarths are an insular and hostile race.." The Morgarths have unique "Kamikaze tanks" for ground combat.
- Sulleps: "The Sulleps are a warlike race with a very strict social structure. From a very young age, Sulleps are subjected to military training. Such is their code of combat, it is more honourable for them to die in battle than surrender. " The Sulleps have unique "Mobile Artillery" units for ground combat.
- Ychoms : "A peaceful trader race that enjoys good relations with Alliance of Free Traders.." The Ychoms have their unique unit as a saucer shaped "Mine Layer".
Space combat is done on a 2D grid where ships are pitted against other ships with a certain amount of hitpoints in real time which can also be paused or slowed down. The player must take note on how to equip all of his ships through various technologies then upgrade them, as well as knowing the limitations of his ships. Ships can also fire missiles in combat by individually ordering and clicking on enemy ships, although ECM systems help in making the missile not hit at all. Shields give their equipped ships another hitpoint layer which must be downed first before damage to the hull can occur. Ground colonies can build several planetary defences and starbases which can fight on their own or automatically aid defending space fleets.
Ground combat occurs when an enemy fleet or one of your own which is carrying tanks attacks a colony and manages to destroy the planetary defences (if any). Your tanks are then controlled in a real-time tactical map after you place them on the battlefield depending if you are attacking or defending. The AI then places its units after you have placed yours. If you are attacking, to seize an an enemy colony you must destroy all enemy tanks and defense buildings. Buildings are affected by power, so by destroying enough power plants on the colony fortifications can be powered down allowing more strategical flexibility. If a player does not have enough ground strength to take the planet, scorched earth tactics are still viable to cripple the colony meaning the AI may need to rebuild those structures.
There are plot-driven FMV and 3D modeled cutscenes to the game along with an opening intro movie. These cutscenes appear whenever you advance in rank and also at certain other points in the game. In the Hungarian version of the game, the intro and cutscenes involve a combination of 3D rendered models and FMV actors, however the English version of the game instead uses extended cutscenes with the rendered 3D models overdubbed with English voice actors. The FMV actors from the Hungarian version however still make an appearance in the English version, but only in the small video messages that are sent to the player from time to time with an English voice acted dub.