Hiromu is 20 years old according to his bio. In Japan you are legally recognized as an adult when you turn 20. Him disobeying his sister's wishes and joining the Go-Busters is basically the same as a kid who leaves home and joins the military as soon as he turns 18.
Not just that. Hiromu himself wanted to join the Go-Busters for the greater good, regardless of her sister's wishes.
The Go-Busters' Camera Gun (Ichigan Buster) has a binocular (Sougan Blade) as an attachment. At first, it may seem rather unusual if not for Rule of Cool, until you realize that their guns are laser guns, and attaching an extra lens will intensify the power. The reduction in lens size will also make the shot more focused and powerful.
Why are there only 5 Busters in total instead of 6 (or more)? Look at the title: Go-Busters. "Go" is "five" in Japan, so the title would translate to "Five-Busters". It wouldn't make sense if there was a Sixth Ranger.
Of course, the Returns special throws this out the window in the alternate timeline, which includes a total of eight team members (though only a maximum of six are shown fighting at once).
At first, naming the enemy mechs "Megazords" seems to be odd. Then the flashback in episode 2 shows that the Megazords originally belonged to the Transport Research Center, going so far as to show one sharing a hangar with Gobuster Ace. In other words, the Megazords are supposed to be the "good guys", it's just that they were captured and corrupted by the Vaglass.
This also explains why they create a Metaroid before sending a Megazord; since the Megazords didn't originally belong to the Vaglass they need to use a Metavirus to override the original programming and make it do what they want.
According to offical material, Go-Buster Ace is also refered to as a Megazord, which makes since with the above Fridge Brilliance. The Megazords could be seen as the mass production version while Go-Buster Ace is the final version.
Episode 2 explains that the Go-Busters are apparently infused with a computer program. Each weakness—overheating after extended use, freezing/locking up, and running out of power without a constant power source—is a computer error.
So what happens with Ryuji in #5 could be likened to overclocking?
Masato's problem, on the other hand, seems to be with obtrusive pop-ups of the Beet J. Stag brand. Appropriately, the latter's ego is akin to the exaggerations this type of advertising relies on.
Even more appropriately is the fact that, not being really in Earth, Masato is technically connected via an Internet-esque platform, so making his issue Internet-related fits even better.
Also, each of the BuddyRoids has what could be considered a 'human' weakness: Nick's lack of any sense of direction, Usada's lack of a verbal filter, Gorisaki's mother hen nature, J's and Ene-tan's egocentric attitudes (not suprising, given that it was Masato who created them), J's Enetron-aholism, and Ene-tan's aversion to being touched.
Mane Lio's human weakness would be it's inability to speak coupled with it being lonely after its creator died.
Yoko is one of the most aggressive female Rangers with one of the most girly Animal Motifs to date - making her a literal Killer Rabbit.
The Go-busters' abilities are similar to their Buddyroids. Hiromu has the speed of a cheetah, Ryuuji has the strength of a gorilla, and Yoko has the leaping power of a rabbit.
Doesn't it only count as brilliance if the so called Fridge Brilliance wasn't blatantly obvious since the prereleased information came out (which all that was)?
The Megazords not having much of a fixed entry time makes an interesting amount of sense when one remembers Enter's discussion with Messiah at the beginning. Messiah's impatient nature and temper tantrums threaten to outright collapse every exit out of hyperspace - so it probably stands to reason that the stability of those routes (and thus the ability to get Megazords out) is dependent on Messiah's mood the very same day.
This also explains why Beet and Stag Busters' Buster Machines can exit Hyperspace in seconds, he's likely using his own route separate from Messiah's and thus unaffected by his moods.
Enter's Verbal Tic of repeating the same word three times (Bon-Bon-Bonjour Go-Busters) could be seen as a corrupted audio file being played.
On the subject of Enter. Why is it that Enter always keeps his glasses when he assumes a disguise? It is because his glasses are connected to the program that allows Enter to assume his disguises!
Alternately to the above, despite changing his clothes, Enter always keeps his goggles, and is implied to need them to see the flow of Enetron, the same way the Go-Busters use their binoculars. This implies that Enter is not quite as machine as he is assumed to be. Possibly even no more machine than the Go-Busters themselves.
Why do the Buster Machines require a Buddyroid to be connected as the control system? It's stated that the Buddyroids have a program that renders them immune to the Metavirus, rendering them unable to be infected by it. Using them as the control system protects the mecha from the virus too!
Beet Buster and Stag Buster don't seem to be part of the original Go-Buster program and were clearly unexpected by the Vaglass. Their intervention happens to harm the goals of both parties (safekeeping the Enetron and taking it into hyperspace). Figuratively speaking and befitting their motif, they are bugs in the system.
Jin Masato getting riled up over Beet J Stag getting in front of him makes sense once we learn that Beet is responsible for transmitting Jin into our world, and turning away from him could mess up the reception, which in turn grew into Jin developing a complex over being obstructed in any fashion.
Alternatively he is like that because the fact that he is a projected avatar means that he is in no personal danger when he fights, but if J is damaged, then it screws both of them over. His seeming attention whore complex is actually a way for him to protect them both.
It could also be due to the manner of how he controls his avatar. If he's doing it from some sort of monitor or the like, J stepping in front of him would mean that he could no longer see.
Jin Masato seemingly clashes with the series' Civilian Powers, until you realize that he's a projected avatar. His power is that he can't be destroyed and can keep fighting for as long as he needs to...unless something happens to J.
In keeping with the computer theme for the powers, Jin basically has backups of himself.
He also has another weakness. That being if his avatar is destroyed or takes serious damage in the real world, Jin will also be harmed in cyberspace. It is implied that if he is destroyed enough times, it could potentially kill him.
Why did Go-Buster-Beet utterly demolish the new Megazord type that Go-Buster-Oh couldn't stand up to? The new Megazord type was based off of BC-04 which Jin designed and built himself. It only makes sense he'd know how to pilot Go-Buster-Beet skillfully enough to outdo a "knock off" of it.
In a simlar vein, look at the Gamma-type Megazords: red color scheme, broad blocky shoulders, and a head aerial? Same blueprints as Go-BusterAce!
Some wonder how Enter can make mechanical monsters out of a pizza cutter or fork. The simple answer? They're simple machines; in this case, variants of the wedge.
Masato gets rightly chewed out for his Dude, Not Funny! inducing "joke" about Ryuji dying if he overheated again. But it is later revealed that everytime Jin's avatar body is destroyed, his real self takes damage, and this can eventually kill him. His use of Black Comedy in light of this revalation makes it seem that he is attempting to make light of his own danger of dying in what is, without a shadow of a doubt, a Crapsack World.
The Buddyroids combining with their partners didn't exactly come out of left field; Jin and J have a similar process occur when they morph together, with J's gold bits appearing on Jin's suit.
The fact that Tategami-Lioh's combinations seem to just involve its replacing Go-Buster Ace (Go-Buster Lioh = Go-Buster Oh - Go-Buster Ace + Tategami-Lioh; Go-Buster King = Great Go-Buster - Go-Buster Ace + Tategami-Lioh) seems strange until you consider the numbers of the Buddyzords.
In episode 38 Enter offers Hiromu a chance to surrender when it seems apparent that he is outclassed by the combined assault of Domezord Gamma and Domezord Delta. This seemingly uncharacteristic display of mercy makes more sense when it's revealed that Enter placed a Messiah Card into Hiromu—he can't let his backup go and get himself killed, and even if the card wouldn't let him die, losing two megazords wasn't in his plans either.
In episode 44 Megazord Zeta stops looking female once it absorbs the other megazords. This is probably because Messiah soon afterwards has a You Have Outlived Your Usefulness moment and consumes Escape, thus Messiah decides that it no longer wants feminine characteristics.
How is Enter able to make Escape copies? Well, she was absorbed by Messiah Reboot, which was born from 3 Messiah Cards. Her data, thus, was sent into Card No. 13, meaning that Enter has her data within him, albeit a watered down copy of it.
Why do Enter's cocoons suffer from No Ontological Inertia after he's killed? He's too Genre Savvy to risk any of them pulling an A.I. Is a Crapshoot when he already did that to Messiah, so he probably made sure that they couldn't function without him, making them easier to control than, say, Avatars.
In many ways, Jin and Enter serve as a Foil to one another. Both are Avatars hailing from Hyperspace, both have used the Beet Buster powers at some point, both have been The Rival to Hiromu at one time or another and both are constantly finding ways to cheat death. The main difference between them is that Enter is a straight example of The Perfectionist, while Jin is an inversion. Jin's capacity to compromise is what enables him to outsmart Enter at the very end through his Heroic Sacrifice.
Why does Sho Jinnai play God in Returns? Because becoming a God was Enter's goal!
Why does Beet and Stag's equipment have a dance-style music theme? Because Beet Buster is bustin' some beats!
Azazel in the Returns special easily beats both Gobuster teams, but is destroyed by them both at once. Why? Not only is he up against twice the number of opponents, the two Sentai have majorly contrasting styles, making it near impossible to mount an effective counter against.
Enter's ultimate goal is to become Perfect. This makes some of his previous actions make more sense: he has a Villainous Breakdown whenever he's outsmarted or his seemingly perfect plans are ruined in a way he couldn't have expected. He was always a perfectionist, it wasn't until Messiah's destruction that he could actually make an attempt at his own agenda.
Most of the Metaroids powered by Messiah's cards have a body part colored red to denote where Messiah is in their body. Enter, who is also powered by the cards, has an all red form.
#5 is steeped in a lot of Values Dissonance - Ryuji's Superpowered Evil Side stems entirely from a special power, and he's depicted sympathetically from having to hold it back though his own effort, even Gorisaki likens his behavior to a 'cartoon villain' as if inducing some Willing Suspension of Disbelief, and thus the incident is easily swept under the rug, which seems a lot like how Domestic Abuse would be treated in a typically rigid Japanese society.
#41 While everyone was focused on Jin's depressing situation, the Messiahroid still managed to datasize a boat and plane, probably had people in it, and it wasn't resolved or mentioned again. Guess the Go-Busters weren't able to keep their promise of an incident like theirs happening to other people. It can be assumed that the people returned once the Metaroid was destroyed, but on the other hand, if Kamen Rider Fourze is to be considered, they are still in dataspace.
It is safe to presume that the people returned offscreen because in computer terms, things tend to reset or reboot and go back to how things were before.
Unless the Go-Busters team have Hero Insurance the city gets damaged on a massive scale all the time, hundreds of people are injured, and car insurance must be through the roof! note In Japan car insurance prices are based different then the US and UK; Japanese companies take into account where you live, how old you are, the average crime rate of your area vs. average police and fire protection, and the distance from hospitals you travel by on a weekly basis.