The game is set fifty years after a tragic catastrophe known as the "Silent Apocalypse". As a result of this event, mysterious alien life forms dubbed "Protonovus" have arrived intending to destroy the rest of humanity. Accompanying the arrival of the monsters was a new element known as "Altenite", the last hope of survival for humanity. To protect themselves from continuous Protonovus assaults, humans created fortified cities armed with weapons of their own. With the approaching "Altered States" and more monster attacks, the inhabitants of the cities must now prepare themselves while they continue to expand and defend their cities.
The player takes control of the urban areas, trying to collect taxes from residents and purchase equipment. During this time, the player can set up the battlefield with his or her own units throughout each layer of the city to prepare for the invasion. When engaged in combat, the player must then use the weapons to repel the approaching enemies and defend their city. Players can also use the "merge" method, which involves placing two or more weapons of the same type on a line to increase the damage on the enemies.
- Addressing the Player: All the characters do this.
- After the End: The game takes place fifty years after the Silent Apocalypse catastrophe.
- The Ace: The player will develop this reputation as time goes on, successfully defending cities thought to be indefensible.
- BFG: When combined, the cannons can become ridiculously huge behemoths.
- Beware the Silly Ones: Most of your crew members have incredibly...odd personalities. They're also capable of defending a city against armies of giant monsters.
- Boring, but Practical: Creating triple missile batteries (i.e. putting three missile units in a row so they combine) pointing in 4 directions (e.g. north, south, east, west or north-east, north-west, south-east and south-west) offers almost 360 degree coverage. Unfortunately, this can only really be done in the later chapters, once the player is able to build units anywhere in the city.
- Big Good: Admiral Neumann.
- Cast of Snowflakes: You have a team of 18 people (20 if you include Dr. Chandler and Admiral Neumann), each of whom has a distinct appearance and personality.
- Citadel City: All the remaining cities are basically these, as they'd be torn apart by the Protonovus otherwise. Part of the challenge is putting together an effective Citadel City that can weather the various types of Protonovus that appear.
- Christmas Cake: Towa fears she's becoming this, and the other bridge crew members sometimes tease her about it.
- Featureless Protagonist: You are the commander trying to defend your city.
- Fiery Redhead / Hot-Blooded: Lovelock.
- Glass Cannon: Strangely enough, tanks. Their attacks will devastate anything they encounter (shy of bosses, and even then only due to the sheer amount of health they have), but at BEST the tanks can withstand one attack — in fact, it's more likely a single attack will destroy them.
- Gun Nut: Most of the gunnery crew fall under this, as they get excited whenever new weapons are developed.
- Improbably Female Cast: 12 members of the team are women, and only 6 are men. If we include the Commander, Admiral Neumann, and Dr. Chandler, that's still only 8 men to 13 women.
- Kaiju: The Protonovus certainly qualify.
- Mission Control: Towa.
- More Dakka: Kind of expected, given the genre. As you build defenses in your cities, their respective arsenals will expand, eventually reaching a point at which protonovus will be bombarded by dozens of attacks before they come anywhere near (unless they spawn directly beside it, of course). And yes, this will overlap with Beam Spam and Macross Missile Massacre at some point.
- Tank Goodness: Tank drones that patrol the perimeter of the city can be developed, but they explode on contact with an enemy. That said, the fact they patrol means they sometimes add their firepower to a beleaguered section of your city.
- Unobtanium: Altenite, the material used to construct and fortify buildings in the city.