Star Fox Assault was the direct sequel to Star Fox Adventures, and returned more to the genre and gameplay of the preceding Star Fox games Star Fox and Star Fox 64. It was published on Nintendo GameCube in 2005. Continuing the trend of all Star Fox games (except 64), the game was not developed by Nintendo itself — this time, Assault was developed by Namco.One year after the incident on Sauria the Star Fox team is hired to help take down the remnants of Andross's forces. However in the mist of this battle a new enemy emerges to threaten the Lylat System. The Aparoids, a race of insect like creatures begin an invasion of the system with the goal of assimilating all life into their collective hive. With the Cornarian Forces outnumbered and outgunned, it's up to Star Fox to track down information leading to the Aparoid Homeworld and defeat this menace once and for all.
Biological Weapons Solve Everything: The game concludes with the heroes attacking the Aparoid queen with an electronic virus intended to induce apoptosis in their biological components. Though she is able to suppress it somehow until you finish killing her with conventional weapons.
The Dev Team Thinks of Everything: Normally, if you fall off a ledge, Fox will immediately reappear on another point of the map. However, if the player does so after completing all mission objectives, Fox is still shown falling down to his death before the results screen comes up.
Earth-Shattering Kaboom: Since the Aparoids have infected their homeworld to the core the entire planet blows up when they self-destruct.
Enemy Mine: Star Wolf, considering what a threat the Aparoids present to everyone.
Everything's Better with Dinosaurs: Averted. There's only one level featuring dinosaurs, and they're all dead. Except for Tricky, who's all grown up and makes a short cameo appearance.
Fantastic Aesop: At the end of Assault, after the Aparoid Queen is defeated, Fox begins getting all philosophical about the bugs' motives, eventually coming up with; "She tried to bypass evolution by stealing souls. But you have to be born with one." The Star Fox team all nod approvingly at Fox's sage words even as the player Face Palms.
From Bad to Worse: The whole story. First, the Aparoids appear years after one destroyed an entire Cornerian fleet. Then, the Star Fox team finds a Core Memory leading to their homeworld, only for Pigma to steal it. Then they find that Aparoids can infect machines. Then they find that they can infect organics, and Pigma is assimilated and destroyed. Star Fox gets that all-important Core Memory, but then they have to rush off and save Sauria, which is being overrun by Aparoids. They save Sauria, only to find that they annihilated Corneria and began assimilating General Pepper while they were busy on Sauria. They finally make it to the Homeworld, only for the Aparoids to assimilate the Great Fox, and for Peppy to perform a Heroic Sacrifice to allow them into the homeworld interior. Star Wolf shows up to aid them, but then they perform another Heroic Sacrifice to cover Star Fox as they enter the deepest part of the core. Star Fox fights through the psychological warfare of the Aparoid Queen, and hit it with the self-destruct program, only for it to not work. Whew. Things are righted after the final final boss battle, but seriously; how bleak can things get?
Not to mention the aparoids appear once Andross and presumably all his minions except Oikonny are dead, and Star Fox is fighting Oikonny. Basically, the threat of Andross is about to be put to an end for all time (unless Command is believed to be canon) when suddenly an aparoid presumably kills him and attacks Krystal, and then the aparoids become the main threat to the Lylat System, but a much bigger threat than even Andross was.
Fungus Humongous: The main form of life on the portion of Katina visited in this game (its previous appearance involved a battle on a more arid part of the planet).
Gatling Good: The Gatling Gun in on-foot missions. It's even more rapid-fire than the (much more common) Machine Gun and, unlike the Machine Gun, has armor-piercing rounds, which allows it to chew through enemies you'd ordinarily need a charged blaster shot, sniper rifle, or explosions to deal with.
Green Aesop: Minor compared to the above-mentioned Fantastic Aesop, but Corneria has a billboard related to cleaning up the pollution on Zoness, which was covered with Grimy Water in Star Fox 64 thanks to Andross's invasion of the planet. Considering the fact that the water in the Zoness multiplayer stage is dark blue instead of green, it seems to be working.
Heroic Sacrifice: Peppy sacrifices himself and the Great Fox to allow Star Fox and Star Wolf to infiltrate the Aparoid Homeworld. Later on, Star Wolf sacrifice themselves to lure the enemies off of Star Fox to make sure they get into the final boss room. Later on, Peppy is revealed to be okay but injured, and Fox hints that Star Wolf could still be alive.
I Got You Covered: Star Wolf does an important role since Mission 7, with Star Fox ultimately failing had they not intervened in succeeding missions.
Just a Kid: The English dialog has Wolf refer to Fox as "pup".
Keystone Army: As powerful as the Aparoids are their susceptible to the apoptosis program developed by the Cornarians. Killing their queen with it can cause the entire Aparoid race to self-destruct all at once.
Lampshade Hanging: Assault is replete with examples of missions in which you have to destroy hatchers in addition to regular enemies. By Stage 9, the assault on the Aparoid homeworld, Fox has become a bit genre savvy about the whole thing.
Fox McCloud: If the past is any indication, there'll be hatchers to go along with those shield generators, right?
In contrast to how most levels aside from Sauria and some new to this game are from Star Fox 64, Fortuna is from the original Star Fox, which was subject to a Continuity Reboot courtesy of 64.
The Star Fox logo returned to a visual style resembling the original Star Fox from 1993.
Wolf's outfit brought back the shoulder spikes that characterized his outfit in the unreleasedStar Fox 2.
No Good Deed Goes Unpunished: The Star Fox team is dispatched to Katina in order to rescue whoever sent the distress signals on the planet, and eliminate the Aparoid menace. Upon defeating it, its revealed that the person who sent the distress signal was actually Pigma, and what's worse, he "repaid" their risking their lives to save the sender by stealing the core memory that Fox intended to retrieve to find out more about the Aparoids to stop their invasion.
Not Me This Time: Star Wolf was initially suspected of being involved in Pigma's theft of the Core Memory. Turns out that, not only were they not involved at all, but they actually kicked Pigma off the team long before it happened.
A meta-example also exists: Because of Star Fox Adventures having Andross manipulating Scales (and for the Japanese fanbase, also having Shears clone him to resurrect him in the tie-in manga), the fans will naturally assume that Andross is somehow involved in the Aparoids' attack. He isn't involved at all.
The Obi-Wan: Wolf advises Fox, which helps him in the final battle.
Fox: Wolf?! What are you doing here? Wolf: You're the one who dropped in unannounced... And if anyone's gonna tan your hide, it's gonna be me.
Outside Ride: The two wing-riding sections where Fox stands on the wing of an Arwing or Wolfen in flight and blasts down perusing enemies with a BFG.
Player Guided Missile: The Missile Launcher in multiplayer matches. It is more powerful than the Homing Launcher, but with a lower ammunition capacity.
Possession Implies Mastery: Averted in the game's Versus Mode, where Star Fox characters have poor Wolfen flying abilities, whereas Wolf has poor Arwing flying abilities.
Psycho Strings: Present in the intro to the music for the Sargasso Space Hideout, which is actually an orchestral version of the music for Sector Y and Solar from Star Fox 64. (However, the original version of the song just had regular strings, and the version in the Nintendo 3DS remake of 64 does as well.)
Ramming Always Works: After the shield protecting the Aparoid Homeworld entrance fails to go down Peppy crashes the damaged Great Fox into it. This drops the shield but destroys the ship in the process.
Saved for the Sequel: During the final mission, the Star Wolf team draw off the enemy ships pursuing the Star Fox team, allowing them to reach the game's Final Boss, and are not seen again, leaving it unclear whether they survived (Although Fox implies in the ending that they did survive). There has been another game released in the series since then and all three members of Star Wolf did appear, confirming that they did survive, though there is ongoing debate among the fandom over whether that game is canon or not.
Shout-Out: The Aparoids, in a last ditch effort to prevent the completion of the Aparoid Vaccination, has various missiles that are both sent via hyperspace wormhole and implied to be powerful enough to destroy a planet should they target it (especially the largest segmented one), similar to the particle disintegrator warheads fired by the Galaxy Gun in Dark Empire.
The Virus: The Aparoids can infect and eventually take over both machines and organic life forms.
Talking to Himself: Both Leon Powalski and Panther Caroso are voiced by David Scully (aka Dimitri from Sly Cooper series). In the Japanese version, seiyuu Yusuke Yumata voices both Andrew and ROB 64, while Hirohiko Kakegawa does Beltino, Tricky, and James.
Averted with Wolf and Fox; Shinobu Satouchi voiced Fox and Leon in 64; Satouchi now only has Leon, while Kenji Nojima now voices Fox. Similarly, Hisao Egawa did both Falco and Wolf; now Mahito Oba voices Wolf.
Krystal and the Aparoid Queen's (real) voice are voiced by Alesia Glidewell (aka Carmelita from Sly Cooper series).
The Worf Effect: Andrew Oikonny is taken down in one shot by the first Aparoid encountered.
Worf Had The Flu: To be fair, he had just been blasted by Fox until both of his robot-hands exploded.