->''"Paradox resolution in my favor. All right. Take that causality!"''

''Achron'' refers to itself as the first "[[RealTimeStrategy Meta Time Strategy Game,]]" i.e. it uses TimeTravel as a functional game mechanic. It's possible to issue commands to units in the recent past or near future, and even send them to different times.

# In additional to the standard real-time strategy user interface, players have access to the [[http://achrongame.com/wiki/index.php/Time_Window Time Window,]] which lets them track, switch perspective to, and order units to time travel to various points in the game timeline.
# Only a small segment of the timeline is actually playable: a range that usually extends from around 6 minutes in the past up to approximately 1 minute in the future. Any events that pass beyond the past edge of the playable timeframe are finalized and cannot be changed.
# '[[DelayedRippleEffect Timewaves]]' are regularly spawned at the event horizon between the mutable and immutable sections of the timeline. These progress up the timeline at high relative 'speed' (default settings have it at 3.1 seconds / second), carrying changes to the timeline with them. Players also act as ad-hoc timewaves; propagating any changes they observe.

A trailer can be seen [[http://www.youtube.com/watch?v=IJ9_zCPjCJs here.]]

Information on the game and ordering can be found at [[http://achrongame.com/ achrongame.com]] and also on [[http://store.steampowered.com/app/109700/ Steam.]] There is also a helpful [[http://achrongame.com/wiki/ wiki]]. Additionally, there is a small demo version of the game.

Not to be confused with VideoGame/{{Archon}}.
!!This game provides examples of...


[[folder: Time Travel Tropes]]
TimeTravel: Basically the ''entire point of the game''.
* Players can control the rate they move through time. This leads to:
** TimeStandsStill: Usually used to set up a complex queue of orders for some units while making sure they hold still.
** BulletTime: Used to better micromanage battles.
** AdrenalineTime: Extension of bullet time: since players tend to slow down during pitch battles and then speed up after the battle to 'make up for lost time', a lot of {{ramping}} occurs.
* DelayedRippleEffect: A gameplay necessity, since if changes to the timeline were instantaneous, games would basically boil down to who sent something to the past first. Timewaves typically travel at three times the speed of time.
* ForWantOfANail / InSpiteOfANail: An important part of the [[ArtificialIntelligence unit AI]] is to ensure player orders happen on every iteration of the timeline when reasonable (i.e. when your opponent isn't actively interfering), so that players don't get frustrated because all of their changes to the past keep undoing everything they've already ordered. Ensuring that one's strategy as a whole happens despite the interference of opponents, while also interfering with their strategies before they come to fruition, is a key component of the metagame.
* FutureShadowing: Standard multiplayer game mechanic. There's also a commonly used tactic based on this called "echo scouting" where a player orders a scout to rush into the enemy's base, skips to the future to see what the scout will find, then skips back to the present and tells the scout to cancel its suicide order in the first place.
* GrandfatherParadox: It's possible to build a mech, send it back in time, and [[TemporalParadox have used it to have destroyed the factory that was going to have built it]]. [[http://www.achrongame.com/site/achron-and-the-grandfather-paradox.php The devs' explanation of how this works out.]]
* TemporalParadox: Why should the GrandfatherParadox get all the love? Ontological paradoxes occur pretty often too.
* JustOneSecondOutOfSync: This trope occurs in a tactic called "Timewave Dodging". If a unit dies in the past, any passing timewaves will propagate its nonexistence into the present. By time traveling it right across the approaching timewave, you can prevent it from being erased from existence. Weirdly enough, you're not hiding from other time travelers; you're hiding from causality itself!
** In a more straight play on the trope you can play one second in the past - you will be able to see your opponent's actions, but he won't see what you're doing until a timewave passes.
* MeanwhileInTheFuture: You can watch and issue commands from any point within a short interval, so it's possible to, say, attack your opponent in the present in order to distract them from an attack that you're [[BatmanGambit about to have begun a minute earlier]].
* MentalTimeTravel: Your primary ability as an Achron. Explained in the campaign as a cross-temporal radio.
* MyFutureSelfAndMe: Ever-present occupational hazard for any soldiers in this game. The duplicates are referred to as 'chronoclones'. Can often lead to...
* MyOwnGrampa: The Grekim are able to pull this off in gameplay (see [[http://www.achrongame.com/forums/viewtopic.php?f=21&t=2903&hilit=Grekim+grandfather&start=20 here]] for directions how). It has little practical use though, so it doesn't happen often.
* HelpYourSelfInTheFuture: You can send units from the future to help their past selves defend the base.
* PlaceBeyondTime: A really strange version of it, at least. There's a section of the timeline that's hard to reach if you don't already know of its existence: [[FanNickname "The Beach"]]. It's a completely empty version of the map you're playing; a region in the future where causality from the present never reached. This is probably the only ''mechanical'' version of the PlaceBeyondTime (other video games simply create an extra, perfectly normal level and give it some backstory).
** It's also completely emergent from the timeline mechanics in such a way that the creators [[GoodBadBugs probably didn't foresee its existence]]. This feature was [[AscendedGlitch kept in]], as it has a few strategic consequences (it's possible to smuggle units across hostile borders by shunting them through the Beach).
** To elaborate on the mechanics, the Beach is the very front edge of the timeline: Stuff that has scrolled onto the timeline but has not been touched by a timewave. In the space between 2 timewaves (50 real-time seconds), that area is "beyond time." After 50 real-time seconds, RealityEnsues.
* RealTimeWithPause: In ''multiplayer'', no less. Bonus points for it being an ''actual ability'' as opposed to a medium mechanic.
* ResetButton: You can undo botched attacks.
* RetGone: Yet another occupational hazard for your forces.
* RetroactivePreparation: A very basic tactic in game.
* RippleEffectIndicator: Various symbols on the timeline are used to indicate various events happening.
* RippleEffectProofMemory: Achrons. The game makes a strong distinction between entities that exist inside and outside time (chronals and achronals respectively). You're a general precisely because of your ability to exist outside the time stream and effect changes to it without being personally affected by it.
* SanDimasTime: The way time travel works actually does a pretty good job of justifying this.
* ScryVsScry: Future-sighting, cancelling your orders in the past, creating red herrings to confuse your opponent's future-sighting and cancelling...
* SetRightWhatOnceWentWrong: An elementary tactic in the game. Which naturally leads to...
* MakeWrongWhatOnceWentRight: ... the dual of the above tactic.
* StableTimeLoop: You can defend your factories with units that they are going to build.
* TeleFrag: [[http://www.achrongame.com/site/blog-main.php#teleport Impossible with teleportation.]] Entirely too easy with time travel.
* TemporalSickness: Units glow softly right after you chronoport them. They're perfectly functional, with the one exception being that they cannot chronoport again until the effect wears off. The effect has thus earned the nickname "rechronoport delay".
* TerminatorTwosome: Your standard two-player game.
* TimeIsDangerous: You need to be careful when sending units back in time that they don't end up [[TeleFrag occupying the same space]] as another unit. Especially their past selves.
* TimeMaster: The titular achrons.
* TimeTravelTenseTrouble: The fans refer to the two orthogonal timelines as "time" (in-game time) and "metatime" (real-life time). Once you hang around the community long enough, it becomes second nature.


[[folder: RTS Tropes]]
RealTimeStrategy: The game is fundamentally an [=RTS=].
* AwesomePersonnelCarrier: All CESO tanks can carry infantry with them, making CESO armies into battlegroups of these. Each race also has a dedicated carrier unit.
* CommandAndConquerEconomy: Partly justified as the structures are all military installations. Which leads to...
* ConstructAdditionalPylons: Primarily Vecgir Power and human Reserves.
* DoNotRunWithAGun: No units can move and shoot simultaneously.
* DualModeUnit: All base class and -pod class Grekim units can enter progeneration mode. They become immobile and unarmed, but can create new units, provided other units of the same class and different type/gender are nearby.
* EasyCommunication: Possible in the present and future, but not the past: giving units commands in the past costs chronoenergy. This leads to an interesting game mechanic of assigning units commanders to create chains of command: you can minimize chronoenergy expenditure by just giving orders to commanders and letting them communicate your orders to their underlings. Also the Comm Jam ability prevents affected units and buildings from being given orders.
* EasyLogistics
* EnemyExchangeProgram: The CESO Heavy Tank, Grekim Octoligo, and Vecgir Shin Halcyon have the ability to infect enemy units and structures with nanites. The subverted units still retain the colour and the ability to take orders from their original faction... but you can give them orders whenever you want to too. Instant spies and/or traitors!
** The user interface itself helps you combat this. Whenever any of your units perform friendly fire, a message is sent to the player warning them about possible nanite infections (and letting them quickly zoom to the offending unit). This message is sent even when the player purposefully attacks his/her own units; it really doesn't know who sent those orders.
** A good use of nanite infection is infecting units that can build. Just let them build turrets somewhere completely useless and watch your opponent's resources dwindle. If you do that far enough in the past, he will probably not have enough Chronoenergy to stop it.
* FactionCalculus: If we equate time travel with sneakiness, then we get... Vecgir (Powerhouse) vs. CESO (Balanced) vs. Grekim (Subversive).
* FogOfWar: In four dimensions; players need to reconnoiter the timeline for data as well as the physical map.
* InstantMilitia: Resourcing is automated by "Resource Processors" and all the constructors from all the factions are military units that just happen to have the added bonus ability of being able to drop buildings (or morph into them, in the Grekim's case).
* NonEntityGeneral: The game makes a strong distinction between chronal and [[RippleEffectProofMemory achronal]] entities. You are the general precisely ''because'' of your achronal nature; which makes a lot of sense since battles in the game are won or lost on the basis of who can out-time-travel his/her opponents.
** In some campaign missions, the AI you play as downloads himself into a unit on the battlefield. If this unit is destroyed you are unable to command your forces for the period when it doesn't exist.
** Another exception is Assassin Mode in multiplayer, where each player is given an 'achron' unit that they must protect or they will lose the game, as well as losing the ability to issue commands at any point where they are dead.
* RefiningResources: All three factions can convert QP (Quark-gluon Plasma) into LC (Liquid Crystal), which is tantamount to converting the more "advanced" / rare resource into the more "basic" / common one... inefficiently to boot. This has less to do with game balance and more to do with [[MohsScaleOfSciFiHardness realism]], since it stands to reason that a player should be able to convert a more refined version of a resource into a less-refined variant in case of an emergency.
* RidiculouslyFastConstruction: It is explained that the build speed is due to rapid [[HandWave teleportation of building materials to the site]].
* ShootTheMedicFirst: The CESO Blackbird can repair units at speeds so fast it can greatly affect the outcome of a battle. This leads to it attracting a lot of focused fire.
** The auto-attack algorithms have now been tweaked so that units prioritize targeting medics like the Blackbird or MFB first! Heck, the trope is even referenced by link within the manual on the Achron Wiki.
* TechTree: Each faction has a very small, very flat tech tree (usually amounting to around six upgrades or so) and they are explained away as "improving infrastructure" (as opposed to "research"). The interesting bit is the way this interacts with the time travel mechanics: It's possible to arm your units with weaponry from the future, or reinforce your army with units you can't technically build yet.
* TeleportersAndTransporters: It is fantastically easy to teleport in this game. The demo tutorials teach you cross-map teleportation before they tell you about ''control groups''. One race can even upgrade units to teleport without a gate, but it isn't as long range. The same race even has a superweapon, a missile, that can ''teleport into the enemy's base''.
* TeleportSpam: Vecgir units tend to do this once they've been upgraded, which occurs automatically once you get Gate Tech.
* YouRequireMoreVespeneGas: All of the races require 'L-Crystal' and 'Q-Plasma', which are found in supply crates left scattered across the maps. WordOfGod is that L-Crystals are basically raw materials for the Nanomachines to build useful things out of, whereas Q-Plasma is used to create the more exotic types of Phlebotinum. CESO (the humans) also has a resource called 'Reserves' which ostensibly looks like Population (its icon is a small stick-figure person, and all units have a small integer cost), but it doesn't act as a unit cap; Importers continuously generate more and more Reserves over time... its closer to a cap on the number of units you can generate per unit time. The Vecgir also have a resource called 'Power' which is provided by most buildings, used by vehicles, and must be above 0 for unit energy pools to recharge.
* WorkerUnit: Each race has units that can build structures, but they are all combatant units who happen to build structures, not workers that happen to have a gun. The Vecgir don't even use mobile units for most of their structures, building them instead from existing structures.
* ZergRush: the Grekim can do this the most easily, thanks to progeneration. May occur with all species in certain situations.

[[folder: Story]]
* AIIsACrapshoot: A sentient, economy-controlling AI did participate in a [[ZerothLawRebellion massive colonial revolt]], but the reason was actually programmed in: The AI was designed to do [[GoneHorriblyRight whatever it took]] to avoid long-term macroeconomic collapse. After this event no further AI of the same type were legally allowed to be created. [[spoiler: However, the human special ops division did create some illegally, and the player character is the sentient, economy-controlling revolutionary AI in question.]]
* AliensAreBastards: The only explanation humanity can find for the destruction of a number of their colonies... for now. [[spoiler: It's actually because humanity's foray into time travel, discovered right as the Grekim attack, is muddying up the timeline and the Grekim do not want that.]]
* ArcNumber: The AI Echo is fond of the number '76,013', [[spoiler:which is ultimately revealed to be the number of StableTimeLoop iterations so far]].
* BadassBoast: [[spoiler:Lachesis, having already managed to survive being destroyed in the backstory for inciting a colonial revolt, points out that the StableTimeLoop between him and the Coremind is just another trap, which he will be able to escape.]]
* CivilWarcraft: In part 1, two of the human factions fight each other at some points. [[spoiler: There is also a faction of Vecgir that, due to being [[InvasionOfTheBabySnatchers captured by the Grekim while young]], are loyal to them, which you must fight in campaign 4]]
* CoolGate: Teleporters, Chronoporters (that facilitate mass teleportation and mass time travel respectively) and Slipgates (that facilitate both) look like cool spinning stargates. Which is a bit [[RuleOfCool unnecessary]] since no unit actually ''walks through them''.
* CrateExpectations: The resources are kept in highly advanced containment devices that can safely store materials which should by rights destroy the continent by a teleporter mechanism that [[TechnoBabble continuously teleports its contents back into the center of the container faster than they can leak out]]. [[OurWeaponsWillBeBoxyInTheFuture They still look like crates though]].
* DecoyProtagonist: [[spoiler:At first it seems like Captain Holloway is the protagonist, with Tyr (the player character) being his VoiceWithAnInternetConnection support, but then it turns out that Tyr is the actual protagonist at the end of the first campaign.]]
* TheDragon: Guardian, a Grekim Keeper (essentially senior officer, but not leader) is trying to rebuild the [[HiveMind Coremind]] to re-unify the Grekim [[spoiler: and destroy humanity in 10000BC. Transforms into TheStarscream once he realizes that he is an individual and he would end up losing that, not to mention that he is the only surviving Grekim leader at his era]].
* EnemyCivilWar: The Vecgir suddenly break ties with the Grekim near the beginning of the story, for no clear reason. [[spoiler: It turns out the HiveMind controlling both of them broke due to Tyr/Lachesis's interference later in the game, which allowed the Vecgir to [[TurnedAgainstTheirMasters revolt and form an independent society]]]]
* GameplayAndStorySegregation: The intention is to avert this. Speaking to the devs reveals that the story is being carefully edited to avoid plot holes or [[MohsScaleOfSciFiHardness softness]] with respect to the in-game mechanics of time-travel, among other things. However, It is possible something might slip through.
* GroundhogDayLoop: [[spoiler:Or rather Groundhog 13000 year loop. Echo has been dug up, used to assist Lachesis and the [[EliteMooks PnC]], chronoported back 13000 years, [[DoubleAgent assists the Grekim in learning enough about Lachesis to enslave him]]. Then gets rebuilt as Jormun, leads then sabotages the Human/Vecgir ground war against the Grekim, and ultimately stops Lachesis from ultimately destroying the Coremind. This has happened 76,013 times at the end of the main game, which means Echo has been around for at least [[TimeAbyss 988 million subjective years]]. It seems to be enjoying itself quite a lot watching the different iterations go by, though.]]
* HiveMind: The Grekim [[spoiler: and initially the Vecgir]] are controlled by the Coremind, essentially a giant distributed AI that uses the Grekim [[PsychicLink Arcticuses]] as nodes, and which connects to all Grekim [[spoiler: and initially Vecgir]] via neural radio transceivers.
* MyFutureSelfAndMe: Captain Halloway meets Captain Halloway-from-five-minutes-later in the first level of the campaign, introducing the [[HelpYourSelfInTheFuture first application]] of time travel for war.
* PortalNetwork: Occurs in the backstory as the human transport backbone. Also occurs in-game to a fashion if you're a fan of the 'slingshot' structure, which can shunt any units that approach it automatically to a point in space anywhere in a wide radius around it. If you build enough slingshots, you can chain them into teleport-bridges that can shunt your forces between all your bases.
* PortalSlam: The focus of the story will be on a group of survivors of the invasion left behind after the aliens destroy the CoolGate which connects them to the humans' PortalNetwork.
* {{Precursors}}: The Remnant system (where the game largely takes place) was named for the ancient remains of alien outposts that can be found on planets throughout the system. The humans most advanced technology is derived from technology found in the ruins.
* RooftopConfrontation: The final level takes place on [[spoiler:the roof of the complex where Guardian has been trying to set up a communications relay to contact the Coremind. It's just you, him, and your armies. Your only goal is to kill him]]
* StableTimeLoop: [[spoiler: In the end, Lachesis is able to defeat Guardian and almost defeat the Coremind 13,000 years before the events at the start. However, some of its component Arcticuses were squirreled away by Guardian, which allows it to recover. It rebuilds itself in Lachesis's image and goes to attack Humanity, thus getting us to the events at the start of the game. Echo/Jormun has been enjoying watching this play out the last 76,013 times.]]
** [[spoiler: This StableTimeLoop also extends to the Vecgir technology used to jumpstart discovery of [[TeleportersAndTransporters teleportation]] and [[TimeMachine chronoportation]] technology. The ruins discovered were actually the bases built by the Vecgir and Humans after the 13,000 year chronoport, thus the discovery of these technologies as they were discovered is dependent entirely on the loop. However, it is highly likely these technologies were originally discovered by Humanity independent of any ruins, but the first iteration of the Grekim invasion and humanity's counter-attack would have caused the loop in the first place.]]
** [[spoiler: Combined with the TranshumanAliens entry about Humanity likely ultimately becoming Vecgir (probably Grekim prisoners from the first few iterations), the existence of the Vecgir, or at least at this era, is an OntologicalParadox. This also explains why all three races use the same resources, as the tech is ultimately either made or stolen from [[HumansAreSpecial Humanity]].]]
* StarfishAliens: In addition to being essentially sentient, technological, time-traveling space squid, the Grekim have 3 genders, Octo, Sepi, and Pharo, which double as unit types. Any 2 genders can reproduce, or progenerate, together to produce a member of the 3rd gender, either of the same unit class or of the next class better.
* {{Nanomachines}}: One of the main resources in Achron is called Liquid Crystals (LC for short) and is made of a mix of common atoms and nanobots in a liquid-crystal framework. When you order a unit to construct a building the unit drops a tiny transponder seed which signals local teleportation infrastructure to teleport the right quantity of LC to that location. The nanobots in the LC then assemble the building using the atoms contained within it. When you build a unit the LC is teleported into the factory where it assembles into the units gear in a similar way (and the pilot is supplied separately).
* TimeTravelEscape: [[spoiler:When cornered and about to be destroyed at the end of campaign 2, the main Grekim capital ship chronoports back 13000 years, in order to allow the [[HiveMind Coremind]] to be contacted at this time in order to get a [[RetroactivePreparation retroactive counterattack]] going against humanity. It is heavily implied that the counterattack in question is [[StableTimeLoop what the player was fighting for the first two campaigns]].]]
* TomatoInTheMirror: Twice. First, [[spoiler:the player finds out that the character they've been playing (Tyr) is in fact Lachesis, the same AI that caused the rebellion mentioned in the backstory. Second, at the end, Lachesis realizes that the Coremind it's been fighting all this time is, to a degree, itself, or at least rebuilt after its image.]]
* TurnedAgainstTheirMasters: [[spoiler:Jormun/Echo turns against humanity in the end, causing Lachesis's ground war on Drasil to collapse and leading to his eventual defeat.]]
* TranshumanAliens: It is not stated outright, but can be inferred that [[spoiler:the Vecgir are in fact the decendants of humanity that have been enslaved and modified by the Coremind in a loop that has been going on for millions of meta-years.]]

[[folder: Miscellaneous]]
* AwesomeButImpractical: It would be possible to create a carefully executed BatmanGambit using the GrandfatherParadox to confuse your enemies to no end - except for the sheer accuracy you would need in timing your actions.
** Also, it would be incredible to somehow make your enemies chrono-frag themselves to death. The question is really, "How?"
** The fandom compiled a LongList of strategies [[http://www.achrongame.com/forums/viewtopic.php?f=73&t=1201#p10185 making use of time-travel]].
* NamesToRunAwayFromReallyFast: The game is developed by indie studio Hazardous Software, which was founded by [[MorallyAmbiguousDoctorate Dr. Chris Hazard]]. Which doubles as...
* AwesomeMcCoolname
* GambitPileup: The obvious result of two enemies with time travel technology trying to turn the tide of the same battle.
* MeaningfulName: Achron is derived from Greek -- the "a-" prefix means "not" or "without", and "chron" is from "chronos", meaning time. In-story, an Achron is free from causality, and therefore outside of time.
* NoBodyLeftBehind: Destroyed units immediately disintegrate in a pretty storm of polygons. This is mostly to make the game kid-friendly.
* TronLines: Units are depicted as mostly-translucent silhouettes with edges that glow with the unit's team colour. This is an interface concession to make your troops easier to spot: according to the setting, all three of the species use advanced camouflage on their military units, making them near invisible.
** This doubles as an explanation for why your units have extremely short sight (insofar as they have RTS-standard near-blind line of sight radii). You can actually ''hear'' battles occurring outside your vision radius.