These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
In Network Transmission when the Professor reveals himself after Zero's defeat, the whole Cyberworld MegaMan, ProtoMan and Zero are standing in inexplicably starts shaking. This shaking is never mentioned again.
Battle Network 4 is filled with these. Although you could blame how the scenario system works as to why nobody ever seems to comment on most of the stuff, it doesn't change the fact that there was some seriously weird stuff going on.
If you look at the series as the continuous story it is supposed to be, the entirety of Battle Network 4 is a massive BLAM. The game ends with a meteor about to destroy the planet, and it's resolved by everyone on the planet cheering for Lan and MegaMan. In BN5, none of this is ever mentioned. Although 4 is given a nod in 5's Colonel version, where the trophies from the 3 tournaments that took place in 4 are on top of Lan's bookshelves.
Breather Boss: Number Man.EXE in the first game, the fact that he never moves insures that almost all of your attacks will be able to hit him.
Freeze Man.EXE in the second game. The fact that he's an aqua navi standing on ice panels causes him to take quadruple damage from any electric attacks, so two Toad Man or Thunder Man chips should be enough to take him down. What's more, since electric attacks causes enemies to be paralyzed rather than flinch, you can immediately hit him again.
Broken Base: The fanbase is decidedly split between those who think the second and third games are crown jewels, and those who think of the fourth game as such. The fourth game is notable for being considered completely abominable by critics and just about everybody else (despite being the highest selling in the series).
Complete Monster: Slur is possibly the worst villain in the EXE saga. No redeeming qualities are ever attached to her. Still doesn't hold a candle to Dr. Weil, however...
Demonic Spiders: Battle Network 3 has the Scuttlest viruses in the Secret Area. They start combat with a Battle Aura that requires a single hit dealing 100 (or 200, for the stronger ones) damage or more to take down, come in groups of three, and have homing attacks that deal 200 damage apiece. To make things worse, you will encounter one that can hit the elemental weakness of the style you are currently using, and they come in groups of 2-3.
Cloudies. When combined with Swordys, they are the stuff of nightmares.
Swordies get kicked a fair bit down the totem pole in later games. Also, in 4, the UnderNet is infested with actual spiders that invade your area, not only forcing you to dance around (you have a Slasher, right?) and put you in the line of fire of everything else, but also covering your section with sticky webs that will catch and hold you for a few seconds, which can generally spell death in the deadliest sections.
Higher levels of most viruses generally qualify for this, given significant boosts in speed and power.
Ensemble Darkhorse: There's a very good reason Mr. Match has been in five out of six games. And why HeatMan is the only Navi he uses is more than one of them.
Higsby HAS appeared more often than the majority of the supporting cast...
Bass. Holy freakin' crap Bass. He might very well be the most popular Navi in the entire series.
Punk.exe isn't especially popular among the fanbase, but his existence is an expression of Keiji Inafune's love of the classic Mega Man Killer (who actually was a darkhorse from the original series).
Other Navis, such as ProtoMan, Colonel, SearchMan, and TomahawkMan, are straighter examples.
Fan Hater: If you like the fourth game, be very careful about which EXE fan you mention that to. Hell, if you like EXE in general, be very careful about mentioning that around fans of the Classic, X, Zero, or ZX series. Verycareful.
Some like to pretend that 4, in its entirety, never happened.
The 4-only bit is generally more common. Admittedly, a good few people have a problem with the whole Disney Death thing, but that doesn't mean that 5 and 6 are cut off so wholeheartedly.
Faux Symbolism: Serenade is supposed to be a perfect being, incorporating aspects of both genders (hence the androgynous appearance), and has attacks named things like "Saint's Light".
Bass, by comparison, is darkness-based like you wouldn't believe. Wants to kill humanity, wields Dark Power from the instant of its discovery, etc.
Franchise Killer: Battle Network 4 had extremely high sales thanks to Battle Network 3, but its poor reception by critics and fans effectively ended things. MMBN5 saw a 33% cut in sales, and they were forced to end the series with 6.
Fridge Brilliance: In Network Transmission one stage has ShadowMan.EXE destroying a critical WWW ID rather than allow MegaMan.EXE and Lan to obtain it and infiltrate their network. The reason why Dr. Hikari was able to reassemble the ID was because the file destruction was done too quickly and not thoroughly enough, making the retrieved fragments MegaMan retrieved after the fight enough to reconstruct the file by various methods of parity-based data reconstruction.
The "Cyberknobs" and virtual gas in the gas-powered heater right at the start of Battle Network 2 might seem wierd, until you realise that they could represent a form of DMA security measure that moves data between memory spaces. Other strange measures that appear to force MegaMan.exe around might represent similar security measures.
Why do you need to get your friend's security codes again each games? Simple: They either changed their passwords, or the security certificates they gave you last game have already expired!
Game Breaker: A lot of the folders you can find on GameFAQs, Gater folders/GateMagic get special mention.
There is also Gospel duping, a bug that allows some gamebreaking folders in 2 to be made.
Don't forget 3's FolderBack chip, easily the most broken chip ever made. It refreshes your whole folder, including itself. Its one and only downside is it recycles the opponent's chips in Netbattles. God help you if they recycled a Navi Recycle and recycle their buffed up chip.
3 is an evil nest of Game Breakers. The big three Navi chip is crazy. One is a field nuke stun, second is a long duration stun and the last hits so many time that a buffed one does sick amounts of damage. It is nearly the same reason why Navi Recycle is so damn broken.
The first Giga Chip you are likely to get are this in 3 (the aforementioned Folder Back and Navi Recycle).
Maybe in single-player, but if you're playing a human opponent, you're just asking for a Heat Spread. A successful hit will usually wipe out most (if not all) of your Grass Stage, and deal Quad Damage to boot. Failing that, any time-stopping multi-hit attack will bypass Undershirt anyhow.
If you have good timing and muscle memory, you can activate the strongest virus of them all constantly. Get the timing down and feed him 100 bug frags and you have a very, very deadly combination, such as life sword range from the swordy family.
In the first game, any chip that deals ≥100 damage. The most HP you'll experience is a thousand - that's right, with one chip, you can take out a tenth of the boss's health. And you don't even need those to use on the Final Boss considering the Eleventh Hour Superpower that you get.
If you customize your health high enough in BN3, Muramasa (deals as much damage as the health you've lost) becomes incredibly powerful with little consequence, because of the fact that the limit of the amount of damage it could go up to was 999, which is enough to nearly kill most high level bosses in one hit (Especially BubbleMan, whose V3 Random Encounter form only appears if your health is at critical).
The Number Trader is a machine in which you can insert passwords to get secret items and powerful battlechips. Double Team in particular had the the Infinity+1 Sword from a Bonus Boss available in it. The passwords are hidden around in scenery or supplementary material, but you can simply look them up on a online guide and heavily equip yourself as soon as the item shop opens.
Good Bad Bugs: You can invoke this by bugging the Humour program. It causes MegaMan's "mood" to change at random, allowing the player to semi-reliably deal x2 damage because it was on full sync or anger for a few seconds.
Also invoked with Battle Network 3's Bug Style, which is all about using various bugs to your advantage.
Bridging this and Harsher in Hindsight, over the course of the early 200x years, malware attacks have increased in frequency and become more high-profile. Between Flame, Stuxnet, and the recent spam attacks made against Spamhaus that threatened to knock out an entire major router node, it's clear that the Battle Network series is eeriely prophetic about cyber warfare.
Extremely debatable. The Battle Network series is the result of a For Want of a Nail with Light researching Internet technology rather than researching robotics like he did in Classic. In Name Only implies that the only thing that ties Battle Network to the rest of the series is the title (and possibly characters). This would probably better fit Mega Man Star Force, but again that might be debatable.
The names make much more sense in Japanese where they were Battle Network: Rockman.EXE and Shooting Star Rockman, since it used the actual MegaMan's names in the title like every other series (except Legends), since the Battle Network MegaMan is Rockman.EXE, and Star Force MegaMan is called Shooting Star Rockman.
Nightmare Fuel: CircusMan in Battle Network 6. He has an attack that the fanbase infamously nicknames as the "Tent Rape Attack". If that isn't bad enough, the first time you see him, you witness him opening his chest to reveal a vacuum, which he uses to absorb and capture one of the two Cybeasts. If that still isn't enough for you, he also successfully uses it on MegaMan later! He's basically Kirby, without the power transformation part and hundreds of times creepier.
Scrappy Mechanic: The Press program which allows Mega Man to walk on the tiny paths. The problem is that while on the tiny paths, Mega Man moves much slower and random encounter viruses still show up, which may cause you to forget which direction you were moving in. There was also the Energy Change program which is required during the Plant Man and Flame Man scenarios where you have to either use a heat (Plant Man) or aqua (Flame Man) element battle chip so you can burn a plant/extinguish a fire which permanently gets rid of your battle chip. The Flame Man scenario gets bonus points since you have to extinguish every single fire and it takes place across several different areas on the internet as opposed to Plant Man's scenario where you only had to burn the plants that were in your way and were only confined to the Hospital's computer network.
While Style Changes are not hated, it is annoying how the element of your style (heat, aqua, elec, or wood) is random.
Also in 4, Dark Chips are all about this. Overpowered chips that appear when Mega Man is "Worried", but upon use, not only do you lose 1 maximum HP after the battle, you're restricted from using SP Navi Chips. Especially bad since you still won't use "dark-type" chips, DS Navi Chips, or Evil Chips like Muramasa or Anibus until you're fully tainted from a lot of Dark Chips. Gets better in 5 where you can use them for the new mechanic Chaos Unison, but you'll only get DS Navi Chips if you use them in their battles.
Regarding Navi fights, Bubble Man and Dark Man's beta forms will only show up if Mega Man's health is low and if there is a bug in the navi cust respectively.
A minor one, but in 3, Dex moves to Netopia late game. As such, you can't jack into his computer or use his shortcut to ACDC Square for some time.
Seinfeld Is Unfunny: Try just viewing videos on YouTube of the fifth and six Mega Man Battle Network games; then try viewing ones of the first and second, especially the first. The first one appears so laggy and bare-bones. (No style changes, no Navi merges...) It's pretty obvious that they were still experimenting. Not to mention, with the amount of Fake Longevity it was hard to get into the first Battle Network game because of all the tedious backtracking, artificially-lengthened stages, and Game Breaker chips.
Sequelitis: The fourth, fifth, and sixth games. The third game rather coherently ended the Dr. Wily plotline, the Bass plotline, and ended with MegaMan's Heroic Sacrifice. Following that the series had a major graphical shift, Style Changes were replaced with Soul Unisons (among numerous other gameplay changes), and Dr. Wily and Bass are somehow still alive. The plots also got quite weird, with the fifth game arguably taking the cake—the Big Bad's plan is to link the literal souls of everyone on earth via the Internet.
Tainted by the Preview: Go ahead. Say you're glad they're keeping the old graphics and Internet in the BN1 remake around fans. I dare you. Although this is because the original Internet was very difficult to navigate, which may be mitigated by the map function also revealed in the preview.
That One Boss: ProtoMan.EXE is usually one of the most aggravating bosses to fight in most games, if only because he tends to block anything thrown at him with his shield until he comes out to attack, which he does very quickly, leaving only a small window of opportunity to strike back.
DrillMan.EXE in 3.
BubbleMan.EXE in 3. The continuous spew of damaging bubbles not only blocks your attacks, but also severely hampers your movement and a new one is made the instant you blow one up. Coupled with all the other obstacles thrown on the field and the fact his third version can only be encountered at critical health...
That One Level: It's not particularly hard, to be honest, but you'd have to search hard to find five or more people who enjoyed the carnival levels in BN4. Brrr... that music.
Actually, what about the waterworks level in the first BN? You have a (somewhat) long stage full of slippery ice. It seems like you deleted what was causing the water to get held up but guess what? Now the water is purple and everyone's poisoned so you have to go through the stage all over again.
For that matter, the Power Plant, also in the first game. While veterans to the series won't mind the lack of post-battle healing (the later games had it as a facet of the system as opposed to a one-time gimmick) there's the fact that you're on a limited battery life, have to solve frustratingly vague logic puzzles, and the random battle rate is through the roof. Oh, and did we mention that a large part of the level is an invisible maze?
In the original game's school network, you have to input passcodes to open gates and the answers are given to you (i.e. count the number of chairs in the classroom, that number is the passcode), however, some gates don't give you any clues meaning you have to guess and if you're wrong too many times, the passcode changes. Thankfully, it does tell you whether you're too high or low and if one digit is correct, you're told which digit to change.
In 2, the Freeze Man scenario requires a lot of backtracking between Netopia and the Undernet.
In 3, the World Three guard robots have security claws that will take you to a certain checkpoint if you get caught. While the claws do have patterns, it can be difficult memorizing them and there are times when a security claw overlaps the shadow of another security claw making it easy to get yourself caught. Some are also ridiculously fast giving you only a few seconds (or less) to run past them while others are incredibly slow forcing you to wait until they pass you.
They Just Didn't Care: The most common theory held by fans as to Operate Shooting Star's lack of new content.
Unfortunate Implications: Mega Man Battle Network 2's "If you don't rescue me, you'll miss the chance to see Miss Yai naked!", anyone?