[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/DefenseGrid_6656.jpg]]
-> "''The invasion began without warning. After a thousand of years of peace, the aliens have returned. The planet's survival depends on activating [[TitleDrop the ancient Defense Grid]]... If it still functions at all.''"
-->--[[AllThereInTheManual Story of Defense Grid]]

Developed by Hidden Path Entertainment and released for the PC in December 2008 (and XboxLiveArcade in September 2009), ''Defense Grid: The Awakening'' is a TowerDefense game that's been hailed as one of the best in the genre.

Over a thousand years ago, an AlienInvasion on your planet was beaten back. Now, the aliens are invading again, and your world is in peril. They've besieged your city, cutting you off from your home. In the nearby ruins of an old military base, you find a dusty terminal and reawaken an ancient ArtificialIntelligence--who, in reality, is the very general of the previous war! After the war his brain was [[BrainUploading uploaded]] into the planetary defense grid, in case the aliens ever returned.

With the help of General Fletcher, you've jumped into the command chair to re-[[TitleDrop awaken]] the grid and SaveTheWorld.

Hidden Path gave the sequel ''Defense Grid 2'' [[http://www.kickstarter.com/projects/hiddenpath/defense-grid-2?ref=live the Kickstarter treatment]]. Though they didn't get enough money to fund it, the project [[http://www.strategyinformer.com/news/23002/report-single-investor-helped-back-defense-grid-2-crowdfunding was funded]] by AscendedFanboy Steven Dengler, who also helped co-produce various DoubleFine projects. It was finally released on September 2014.

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''Defense Grid'' provides examples of:
* AirborneMook: Darts and Mantas. Both of which do not take the usual route which the other mooks do, and instead travel another fixed path and if they manage to steal one of the cores, they're considered to be lost immediately and can't be recovered even if you manage to shoot them down before they escape.
* AlternateRealityGame: Is one of the 13 indie games that form the bulk of the material of Creator/{{Valve|Software}}'s "[[http://valvearg.com/wiki/Valve_ARG_Wiki PotatoFoolsDay]]" ''VideoGame/{{Portal 2}}'' ARG.
* AndTheAdventureContinues: The end of the ''Containment'' campaign, presumably to set up a SequelHook for ''Defense Grid 2''.
* AntiAir: Missile towers can only attack air units, but they do a very good job at it and have a large radius.
* ArcWords: ''Defense Grid 2'' give us a rather silly one: "Raspberries". But it turns out to be ''a lot'' more significant than it seems.
* AscendedFanboy: Steve Dengler, see above.
* BewareTheNiceOnes: General Fletcher is overall nice, optimistic and lively, but can be quite threatening if angered.
-->'''General Fletcher:''' Bastards! I only wish there were more of you to kill!
* BigBad: [[spoiler:Advisor Zacara]] in the sequel.
* BigDamnHeroes: General Cai saves your back with the orbital laser in the Containment DLC of the first game when you have to face Crashers and Juggernauts much earlier than expected.
** Later you repay the favor by saving ''the entire population of a planet'' by stalling the aliens while they flee in space shuttles.
--->'''Simon Ritter:''' Commander, Fletcher, thanks for all the hard work. If it wasn't for the two of you...
--->'''General Fletcher:''' You would have been fine... Probably. Possibly. Well, actually... You're welcome.
* BigGood: General Fletcher.
* BiggerBad: [[spoiler:The Alien Queen, whom Zacara was attempting to strike a deal with]] in ''Defense Grid 2''.
* BloodKnight: General Fletcher in the sequel who's a bit too eager into blasting aliens to oblivion, even more so if they anger him.
-->'''General Fletcher:''' I'm ready! [[PlayerCharacter The Commander]] is ready! Let's kill them all!
* BoringButPractical:
** Doubles as SimpleYetAwesome. Once they're fully upgraded, Gun Towers are one of the best damage-dealing towers available. They're also the cheapest tower to buy and upgrade, and they're effective against nearly everything, working against both flying and ground enemies and rapidly destroying shields. ''[[UpToEleven Even more so]]'' in the sequel where Gun towers can have one passive upgrade that ranges from damage over time, to shield piercing rounds, or even area damage, giving it more flexibility to adapt Guns for your strategies.
** Temporal towers. Aside from a nice lightning effect all they do is slow down enemies... Which helps immensely when dealing with anything but flyers. They also have a stable, constant, upgrade cost rather than getting more expensive as it levels up.
** In the first game, Command towers. They don't do anything fancy or flashy, but they do reveal stealthed aliens and give an increase to your much needed resource gaining if anything dies in their (rather generous) range.
** In the sequel you have Boost towers. Cheap but they don't do anything besides blocking aliens' path on their own, but a tower built on top of a Boost can have a number of other bonuses on them ranging from damage, to invisibility and shield disruptor, to score booster.
** Admiral Phillips' skill in ''Defense Grid 2'', it's no death laser, tower buffing or resource gaining ray, but it allows the player to pick a priority target so all towers will focus fire on it. Particularly useful against troublesome targets like Landing Pods and Rumblers.
* BottomlessMagazines: Gun towers are explicitly stated to have infinite ammo, yet the last step of their unfolding animation when you build or upgrade one involves audibly reloading their guns.
* BondOneLiner: General Fletcher has a surprising amount of them for specific towers when they kill a boss level alien.
-->''[If a boss is killed by a Gun tower]'' '''General Fletcher:''' Raw firepower has its uses.
-->''[If a boss is killed by a Inferno tower]'' '''General Fletcher:''' I believe the proper word is "toast".
-->''[If a boss is killed by a Laser tower]'' '''General Fletcher:''' I think the poor devil has seen the light... A bit too much of it.
-->''[If a boss is killed by a Cannon tower]'' '''General Fletcher:''' He's way beyond shell-shocked I think.
-->''[If a boss is killed by a Meteor tower]'' '''General Fletcher:''' Unfortunate for them that they didn't look up first, isn't it?
-->''[If a boss is killed by a Tesla tower]'' '''General Fletcher:''' Is it raining? I saw lightning...
-->''[If a boss is killed by a Concussion tower]'' '''General Fletcher:''' That fellow went boom-boom.
* BrainUploading: General Fletcher, who stopped the previous invasion is now the AI running the defense grid. He often talks about things he would do if he was still in his body. Mostly eating raspberries.
** The ''Containment'' campaign introduces Cai, in control of a different planet's defense grid.
* CanonImmigrant: [[VideoGame/{{Portal}} Guess who stars]] in the expansion ''Defense Grid: You Monster''? [[http://www.hiddenpath.com/games/defense-grid-you-monster/ Hint: Not Chell.]]
* {{Cloudcuckoolander}}: Spending over a thousand years uploaded inside a defense computer network has left General Fletcher a little... Odd, [[SubvertedTrope but he realizes how he's acting]] and resolves to stay focused on repelling the invasion.
** In ''Defense Grid 2'', General Cai becomes one [[spoiler:after being kidnapped by the aliens to have parts of her code removed]]. Professor Briel and Colonel Rissler all share the same oddity saying weird things every now and then.
--->'''General Cai:''' I'm still 149% ''peach frosting''!
* CompetitiveBalance:
** Gun towers are JackOfAllStats. Cheap and reliable with good damage against every type of alien. Flexibility and low-cost are the best traits of Gun towers.
** Inferno are [[SkillGateCharacter Skill Gate Towers]]. It's the first tower available to do damage to groups of aliens, but can be easily outclassed by Concussion or Meteor towers.
** Laser towers are a mix between JackOfAllStats and GradualGrinder. It's heat beam can easily destroy fast enemies via burning caused by its ray, but it's a bit weaker than the Gun tower and practically useless against shields.
** Cannon and Meteor are [[LongRangeFighter Long-Range Fighters]]. Very high damage at high distances, but can't shoot anything very close to them.
** Concussion serves as CloseRangeCombatant dealing constant damage to anything withing its range, extremely effective against large groups of small enemies that can diverge the attention of other towers, however it fares poorly against heavily armored enemies like the Crasher.
** Command towers act as a counter StealthExpert revealing enemies with stealth within its range allowing towers to attack them earlier and also increases the resource income.
** Tesla towers have MightyGlacier properties: it can attack constantly with low power, however it takes a while to charge to full power, but if it does it will deal massive damage on the next hit. Teslas are also very effective against shielded aliens.
*** In the sequel Teslas end up being MasterOfNone, good damage against single targets which will chain to another giving it some crowd control properties, but it is easily outclassed by any other tower that focus on that specific role. Even it's shield-breaking ability is easily replaced by a Boost tower upgrade (Disruptor) which also disables stealthed enemies.
** Missiles have the highest damage output in the first game but suffers from CripplingOverspecialization since it can only target airborne aliens.
*** In the sequel they become [[MightyGlacier Mighty Glaciers]] being able to target ground enemies with powerful, single target (without an upgrade) missiles, but with a pretty slow fire rate.
* {{Crossover}}: The ''You Monster'' expansion crosses over with the ''VideoGame/{{Portal}}'' series.
* DamnYouMuscleMemory: If you are playing versions of ''Defense Grid 1'' and ''2'' on PC and is used to the numerical shortcut to create the towers you might build something you didn't intend to when swapping to another game.
** For Tower Defense genre in general, '''especially''' in ''Defense Grid 1''. You might want to spend your resources as soon as you can and build as many towers as you can, but if you do it there you probably '''won't''' earn a Gold medal even if you win with all cores in the base. The game encourages the player to use as less resources as possible and play conservatively using them only when really necessary; the more resources you have, the more you will earn via interest, and in the end it might be the difference between a Silver or Gold medal in the rank. Both games also have "rewind" button which allows players to go back to a previous checkpoint, encouraging even further players to test tactics using as less towers as possible.
* DeathFromAbove: The Meteor tower; incredible range and deals area-of-effect damage.
** In the sequel characters can use a satellite to fire a beam with varying effects. General Cai sometimes even says "Death from above!" word by word when selecting her as commander.
* DeflectorShields: The Bulwark uses these to protect itself. The Spire's can protect other aliens. The already unfair [[MightyGlacier Crasher]] is given these to make TheJuggernaut. Inferno and Laser towers can barely scratch them, while Tesla towers are SuperEffective.
* DoWellButNotPerfect: If you are having problems getting a gold medal, sometimes it's better to go easy on the final enemies and let them live live a little longer with a softer defense while the interests rack up your resources towards the gold score.
** Similarly in the sequel it's best to kill enemies as late as possible as you'll be gathering resources meanwhile. The more resources you have when you kill something the more points you'll earn.
* DownloadableContent: In the form of map packs. The Resurgence series is four packs of two maps each, Containment is a short campaign of eight maps, and You Monster is a crossover with ''VideoGame/{{Portal}}''.
* DungeonBypass: Later levels have you build TheMaze yourself using towers. [[AirborneMook Flying enemies]] go right over it, and instantly leave the map when they reach your power cores.
* EarlyGameHell: Some maps in both games would be a whole lot easier if you had access to the final upgrade level or a certain tower in your possession.
* ElementalRockPaperScissors: Sort of. Gun and Cannon towers (Projectile damage) do well against whereas Inferno and Laser (Fire damage) is inefficient against shields, but is effective against speedy enemies. Tesla (Energy damage) is very effective against shields, but has only average damage against anything else.
* EliteMook: The description for the Rhino states that it is the basic elite unit of the alien army.
* ExcusePlot: [[TropesAreNotBad A well-done example of one.]] It's a rare thing to see a Tower Defense game with CharacterDevelopment.
* ExpansionPack:
** ''Borderlands''; four extra levels included as free DLC.
** ''Resurgence''; four smaller [=DLC=]s with two new levels apiece.
** ''You Monster''; a ''VideoGame/{{Portal}}''-themed campaign.
** ''Containment''; an eight-level campaign funded by the ''Defense Grid 2'' Kickstarter, and some community-made levels included for no extra cost.
* ExpositionFairy: General Fletcher himself.
* FaceHeelTurn: [[spoiler:Advisor Zacara]] near the end of ''Defense Grid 2''.
* FragileSpeedster: Racers can only take about as much damage as a regular walker, but they are a lot faster.
* FrickinLaserBeams: Laser towers, which are good against the two fast enemies, the Racer and the Rumbler, both because the said enemies keep taking damage from being set on fire by the laser after they're out of their range and because lasers don't have to waste any time pivoting to aim at an enemy when it enters its range.
* GatlingGood: The level 2 gun tower swaps out the chain gun with a tri-barreled gatling gun. The level 3 gun tower adds a second one.
* HellIsThatNoise: You'll learn to fear and hate that "zap" sound whenever aliens get a hold of your cores. If one of them runs with your core General Fletcher will leave a distressed commentary.
-->'''General Fletcher:''' No, no, NO! Not another core gone!
** If the aliens grabs all cores from your base (but doesn't leave it) General Fletcher will comment [[OhCrap the power is low, thus indicating your interest is basically nonexistent]].
** The high-pitch alarm that sounds when flying enemies enter in the map will make you go OhCrap if you forgot to arm defenses against them.
** The subtle sound indicating Landing Pods are about to drop in ''Defense Grid 2'' will make you double-check your defenses quite fast.
** In ''Defense Grid 2'' Suppressors make a high-pitch zapping sound when they die, something you learn to hate quickly as it also jams your towers.
* HarderThanHard: ''Defense Grid 2'' gives us the Elite difficulty with faster and stronger aliens.
* HeroicSacrifice: Cai attempts one in the first game in a TakingYouWithMe maneauver. [[spoiler:Fletcher and the Commander are having none of this, though]].
* KillItWithFire: Inferno and Meteor towers are strong against [[ZergRush Swarmers]].
* KillSat: The orbital laser obliterates anything, but is slow to charge and enemies killed by it give no metal to build and upgrade towers with.
* LighterAndSofter: ''Defense Grid 2'' is far less depressing than the first game.
* LightningGun / ShockAndAwe: The Tesla tower. Its attack is stronger if given time to charge up, and it can [[ChainLightning chain enemies]].
* MeaningfulName: Almost all the {{Mooks}}.
** Swarmers ''always'' [[ZergRush appear in swarms]], unless they're periodically released from a [[MookMaker Seeker]].
** Rhinos are [[HeavilyArmoredMook heavily armoured]] and can take more damage, similar to how the real life rhinoceros has a thick armour.
*** In the sequel Rhinos can charge much like a real rhinoceros. They do have to slowdown to turn, though.
** Racers are [[FragileSpeedster very fast enemies]].
** Darts have a dart-like appearance, and they can [[AirborneMook fly]] like one too.
** Mantas looks kind of like manta rays, and also [[AirborneMook fly through the air]] in the same fashion the manta ray glides underwater.
** A bulwark is a protection against external attacks. Bulwarks have DeflectorShields that protects them from damage.
** A spire in real life is a pointed structure. Spires in this game are shielded aliens that have a pointed head.
** Lurkers have the ability of stealth protection and can "lurk" away from your towers.
** Decoys give stealth to units around it but do not have stealth themselves. Thus, they act as a decoy and attract attacks from your towers towards it, instead of the enemies it gives stealth to.
** Turtles have heavily armored shells, like a real life turtle.
** The Crasher tends to inexorably crash its way straight through whatever you throw at it, while its shielded counterpart TheJuggernaut is, well, nigh unstoppable unless you have strong weapons.
* MarathonLevel: The Grinder and Super Grinder challenges pit you against '''99''' waves. And yes, you ''still'' must finish to obtain medals. The score requirements are quite low in proportion (ideally, you'll hit ''at least'' one million on these sorts of challenges out of the 100,000-200,000 needed for gold), but if you so much as lose a single core, there goes about an entire hour of your efforts.
** Adrenaline and Shredder challenges are not as long, but still far longer than any level in the game, they can have '''50''' waves to fight.
* MemoryGambit: Fletcher deliberately omitted certain memories when he was uploaded, to ensure the aliens wouldn't find out about them-- namely, the existence of other human colony worlds and [[PortalNetwork the portal]] that led to one of them.
* MetaPowerup: Command Towers are these--they don't add any extra power for your towers, but they will reveal Stealth units and also allow you to gain more [[YouRequireMoreVespeneGas resources]] from any enemies killed in its range.
** Professor Briel's skill, it transfer resources instantly on the use, increases the more aliens you hit with it, which is quite useful especially early on.
* MightyGlacier: Crashers and Juggernauts. These guys can make off with three power cores at once, but due to their size and weight, they are slooooow (in fact, they are the slowest of all the aliens).
* MinimalistCast: Just the unnamed player character and Fletcher. ''Containment'' adds two more, Cai and Simon Ritter.
** Averted in the sequel which adds a fair bunch of new characters.
* MoodWhiplash: If you [[GameOver lose all of your cores]], [[ItsAWonderfulFailure you get to hear Fletcher's melancholic last words as the grid shuts down]]. Right afterwards, the post-battle menu screen shows up and Fletcher cheerfully encourages you to try again.
* MookMaker: Seekers periodically open a portal to the enemy aliens' home planet, allowing (usually) smaller but weaker aliens to join the fray. In the final campaign level, there are Seekers that will generate nigh-endless waves of Crashers and Rumblers if they aren't dealt with.
** Turtles are heavily armored boss enemies that carry weaker {{Mook}}s inside, which are released when the Turtle is defeated. In later levels, they carry even the [[LightningBruiser Rumblers]] boss!
* MultiMookMelee: The standard gameplay, taken to the extreme in the Grinder and Super Grinder modes.
* NoGearLevel: In ''Containment'' [=DLC=], the level Foothold has you only with your basic towers (Gun, Inferno and Laser). [[spoiler:Since you went through the portals aliens were using to try another invasion, after you thwarted their first, Fletcher still needs to re-power the new grid for the other towers]].
** In ''Defense Grid 2'', Double Take deprives you of any special ability. Justified by the fact the abilities are modified versions of a satellite beam and you're defending an orbital elevator.
* NoFairCheating: If you completely block the aliens' path to the cores, they'll simply walk right past the offending tower. Depending on your tower composition, this will result in a shorter path than you planned for the aliens, which is very, ''very'' bad.
** The sequel prevents this from happening by simply prohibiting the player from building anything that would completely block the aliens' path, this also prevents the player from accidentally placing a tower where it would completely block their path and thus, inadvertently creating a "shortcut" for the aliens.
* OfficiallyShortenedTitle: The sequel is abbreviated simply to ''[=DG2=]''.
* OhCrap: In the sequel Simon has a pretty big one upon seeing a giant alien space ship stationed close to the cores.
-->'''Commander Simon:''' Area looks clear. You know, clear except for that ''GIANT MONSTROUS ALIEN SPACESHIP OVER THERE''. [[SarcasmMode You know. Clear.]]
* OneHitPointWonder: Some stages have challenges that give you only a single core.
* PyrrhicVictory: The first game has an achievement by the same name, which is earned by killing a flying alien who has taken a core. Since cores snatched by flying enemies are permanently lost even if they are destroyed the name of the achievement is pretty fitting.
* RandomDrop: In an odd fashion in ''Defense Grid 2'': Every time you finish a map you have a chance of earning a tower item which varies from 01 to 05, you may earn an item of 01 or sometimes, in very rare cases, an item at grade 05. Playing on higher difficulties and longer maps significantly increases the chance of earning better, and rarer, tower items, though.
* RidiculouslyFastConstruction: Towers rise up almost fully assembled from hatches in the ground. [[JustifiedTrope Justified]] in that you are re-activating an existing defense grid, and the resources you are gathering are effectively repair parts for existing components.
* SequelHook: ''Defense Grid 2'' ending. [[spoiler:After foiling Advisor Zacara's plan to use MindControl on the aliens to create her own army, she is possessed by the aliens and they leave an ominous message about they will return and this time they ''won't'' underestimate Fletcher]].
* ScoringPoints: At the end of a mission, you're given points based on how many Resources you have, the sell value of your towers (which is always less than the buy value, ensuring that buying and upgrading towers will reduce your score), and how many Cores you have intact. You're also given medals for hitting point milestones. Thus, maximizing score and getting those gold medals is based around efficient Resource use while preventing your Cores from being stolen.
* ShellShockedVeteran: General Fletcher is often overcome with the tragedies he's experienced a thousand years ago. At one point he briefly thinks he's still fighting the previous war.
* ShoutOut: [[Theatre/HenryV Once more into the breach!]]
* TalkativeLoon: Professor Briel is this in ''Defense Grid 2'' thanks to the aliens messing with her [=AI=] code. Lampshaded by General Cai later on.
-->'''Colonel Rissler:''' This is quite the mining facility. I don't know that I've ever seen anything like it.
-->'''Professor Briel:''' Indeed. It curb friend will be stationary plume decadent responding.
-->'''[[DeadpanSnarker General Cai]]:''' There goes Briel's vocabulary again. Time for a reset.
* TheGoomba: Training drones in the first stage are very weak and can only carry one core. That's the ''only'' time you will fight them, though.
* TheMaze: Making them with towers is necessary to slow down alien progress long enough to keep them continously exposed to your attacks. The DLC map Height of Confusion is nothing but one big grid of tower slots, requiring you to structure the level yourself.
* TheUnreveal: [[spoiler:None of the games actually reveal why the aliens are invading and what they are really after or even why they want the cores you go through hell to protect]].
* TookALevelInCheerfulness: General Fletcher grew to be a lot more lively ''and'' [[DeadpanSnarker snarky]] in the sequel.
* TrademarkFavoriteFood: General Fletcher really loves raspberries, although he also enjoys blueberries too.
* TurtlePower: One of the enemies is actually called the "Turtle". It has a lot of health, and just like a turtle, contains [[MookMaker stuff]] inside its hard shell.
* UnexpectedGameplayChange: In ''Defense Grid 2'', Power Outage challenges forces the player either to keep their cursor close to the towers or build them close to the core housing, otherwise they won't even activate and shoot aliens.
* UnstableEquilibrium: If you design a very efficient layout minimizing cost, the unused energy generates interests, in turn making the game easier as you'll eventually reach a MoneyForNothing point. If however, your defense is hard-pressed, you won't have much help from the interest rate. In addition, unreturned cores (which also lower said rate) are harder to defend so the next wave of enemies gets more dangerous than it should be with a static defense, relay-races with cores are common and pestering in that scenario.
* WakeUpCallBoss: Ancient Research in ''Defense Grid 1'' is the first map to feature boss level aliens, the Crashers which are tough and '''very''' resilient and can carry up to ''three'' cores. The game only gets harder from that point on.
** 07 - Split Decision on ''Defense Grid 2'', it's the first map with two core housing which forces you to learn to balance your resources to protect both and it's the first level to feature [[MightyGlacier Crashers and Juggernauts]].
* WhamEpisode: In the first game, [[spoiler:Containment]], when the aliens launch an attack to your home city.
** In ''Defense Grid 2'', [[spoiler:Mission 19 - Out of Control]], explains who's behind the kidnappings of [=AIs=] and the cause of their loss of memories.
* WithThisHerring: Justified by the fact General Fletcher has to slowly reactivate the towers since they've been offline for who knows how long.
** The sequel starts with Simon, Fletcher and Cai investigating a distress signal, but not quite expecting another alien invasion, thus the grid can only activate few types of towers.
* WhoWantsToLiveForever: General Fletcher.
* YouRequireMoreVespeneGas: Towers are built and upgraded with a single Gold-type resource from killing aliens which doubles as your score, along with the remaining cores and total sell value of your towers at the end of the level. The game encourages minimal use of resources through interest.
* ZergRush: Swarmers. Weak health, but damn, they come in large ''swarms''!
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