The game takes place in a ravaged future, where constant warfare between nations have destroyed much of the world's surface, turning it into a polluted inhospitable wasteland. The remnants of the nations are forced to live in isolated havens known as Domes and struggled to survive on whatever resources they could stockpile. One by one, the Domes fell, until only one Dome remains - the Federal Dome, and ultimately what's left of humanity. They are now struggling to fight for their survival as their very existence is being threatened by the barbaric and fanatical Raak-Zun, a race of mutants evolved from humans who were left to die in the outside world and certainly held a grudge for that. Not that the Raak-Zun aren't without their own problems...
A prophecy speaks of an individual, the Heretic, who would lead a rebellion against the Raak-Zun tribes, resulting in an all-out war between the splintered tribes. In the midst of this chaos, the Heretic would ascend to become the physical embodiment of their god, Raak. The Heretic has already began planning the rebellion, having found a teleportation device to the mysterious tropical planet Elysium and having build his own army there. Said planet is also home to a race of sentient machines known as the Sentinel, created by an unknown Master Race. It is unknown what their purpose is on Elysium, but their hostile nature would spell trouble for the Federation and the Raak-Zun, especially when they start invading Earth.
Sun Age: Battle For Elysium contains examples of:
- Action Bomb: Two Raak-Zun units, the Demolition Machine and upgraded Slaves.
- After the End
- Almighty Janitor: Raak-Zun Slaves can be used as combat infantry when a Slavemaster is attached to their squad and can still carry on building/repairing stuff. They are reasonably good at dealing with infantry and can be upgraded with a suicide bomb ability that makes them deadly to vehicles too. The fact that they cost no resources to build (just manpower) meant it was easy to amass and rush the opponent with them.
- Cool Bike: Raak-Zun Slingers, buggy-like trikes armed with rockets. Good at dealing with ground and air vehicles. They can also be upgraded with the ability to deploy into static AA defenses which can tear aircraft apart quickly with their Wingeater missiles. Their sight range is also increased while in this mode.
- Cool Car: The Federal Cougar is about as cool as it gets. Its available at tier 1, cheap and quick to produce, reasonably armored, very mobile, and it's twin rapid fire cannons can make short work of most vehicles and structures. It can also be upgraded to utilize a powerful radar that doubles it's speed and sight range, making it an excellent scout/spotter, but prevents it from using it's weapon while its active.
- The Raak-Zun on the other hand have the Scavenger. Its armed with a long ranged machine gun turret, great for picking off infantry on the go and from a safe distance. It can also be upgraded with the ability to transform into a short ranged, forward firing mobile flamethrower to better deal with most ground units at the expense of versitle long range capability.
- Deflector Shield: Federal Warhawks can be upgraded with the ability to generate one, protecting them from incoming fire but disables their weapons. Sentinel Drone Soldiers can also be upgraded with one, albeit forward facing, absorbing several hits before the shield shuts down.
- The Sentinel Behemoth can be upgraded with an inverted shield, that damages surrounding enemies while healing itself.
- Dual Mode Unit: Nearly every unit in the game has a special attack or an alternate mode that must be researched first before they can be used. Some of these turn basic early game units into nasty mid-late game threats.
- Explosive Overclocking: Sentinel Striders can be upgraded to utilize a one-shot Wave-Motion Gun that destroys them when fired.
- Faction Calculus: Federation (Balanced), Raak-Zun (Subversive), and Sentinel (Powerhouse)
- Kill It with Fire: A Raak-Zun specialty, a number of their units are armed with damaging flamethrowers which can engulf multiple infantry and inflict burn damage to them. Such units include Incinerator turrets, upgraded Scavengers, and the worm-like Spawns created by the Spawnfreak.
- Mêlée à Trois: Federation vs Raak-Zun vs Sentinel
- Playing with Syringes: The Raak-Zun, having fanatically embraced constant evolution, aren't afraid of conducting brutal genetic and cybernetic experiments in order to create twisted Super Soldiers such as Mutants, Cyborgs, Golgothas and the Spawnfreak.
- Poisoned Weapon: Federal Icarus Bombers can be upgraded with the Daisycutter bomb which, despite being named after the Real Life fuel-air bomb, explodes into a wall of toxins that instantly kills organic infantry. Sentinel Haymakers can be upgraded with toxin warheads that leaves poison gas in it's wake, again deadly to organic infantry.
- Psycho Serum: Raak-Zun Mutants can be upgraded with the ability forcefully increase their metabolism, rendering themselves Nigh-Invulnerable to any damage but kills them after 20 seconds.
- Spider Tank: Sentinel Stalkers. Scuttlers don't really walk with their spindly legs; they hover about and use the legs as landing gear. The Raak-Zun has Golgothas, elite cyborgs whose lower bodies are taken up by a set of heavy mechanical legs.
- Worker Unit: Each faction has one (two for the Federation) that are used for base building and resource harvesting:
- The Federation have M.D.Rs and M.O.L.E Trucks, used for base building and resource harvesting respectively. M.D.Rs have the standard ability to deploy into a backup Transmitter, quickly and temporarily connecting loose Transmitter networks, while the M.O.L.E Truck...just mines.
- The Raak-Zun have Slaves, which only require manpower to produce and come in squads of five. They can be used as combat units when a Slavemaster is attached to them and can be upgraded into suicide bombers.
- The Sentinel have Scuttlers. They can be upgraded with Invisibility Cloak and deconstruct enemy buildings for resources.