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.
Quint is probably the absolute king of this trope, as he is almost so vague, people are bound to interpret him completely differently. MS Paint Masterpieces, in particular, depicts him as a Knight Templar.
This fan video offers a rather popular and twisted take on the series. Mega Man is a mindless, hypocritical psychopath who thoughtlessly slaughters robots by the hundreds because they stole some factories. The horrifying thing is, if you go off of the games and the games only, that's not entirely implausible. Bomb Man lampshades just how terrifying and disturbing of a person Mega Man would be viewed as in real life.
Anti-Climax Boss: Given his backstory, Quint should be one of the most epic bosses in the series. In practice, most intro bosses put up a better fight.
In 3, we're introduced to Shadow Man, who, according to source material, is possibly alien in origin and was used as a basis to build the 7 other Robot Masters. Never before has an alien concept been played with, and it wasn't seen again until 8, which seemed completely unrelated. 8 as well may count, reintroducing the alien robots concept and not expanding on it.
Director Displacement: While he was the lead artist on all the games up to 8, Keiji Inafune didn't actually become the head designer until partway through production of 3. The first two games were designed by Akira Kitamura, while the third was initially designed by Masayoshi Kurokawa, who subsequently quit during production, forcing Inafune to take over.
Though nowhere nearly as popular as Proto Man, Roll is very popular thanks to her kindhearted personality, her unique fighting style in Tatsunoko vs. Capcom, and her catchy theme song "Kaze Yo Tsutaete".
The Mega Man Killers. As if the fangasmic explosion of cheers when they were revealed as Bonus Bosses in 10 wasn't enough of a hint. Inafune himself considers Punk to be one of his favorite characters from the classic series, and drew up the design for the Battle Network incarnation of the character.
If Dr.Cossack (and/or his daughter Kalinka) appears in any adaptation, especially outside of the game he actually was in, the fans WILL cheer.
Double points if Kalinka finds her way into a work based around Mega Man X. But not if she builds Axl.
The Robot Masters in general tend to get a lot more love than the majority of oneshot bosses like Gleeok or the Armos Knights. It's probably their interesting designs, which ooze with character, and their catchy stage themes, which inevitably get associated with the Robots themselves. The 1, 2 and 3 Robot Masters are especially popular, in accordance to their respective games. Cut Man, Guts Man, Shadow Man, Quick Man and Crash Man gets special mention.
Even Better Sequel: 2 is considered one of the textbook examples in gaming history. It took everything that was great about the first one and improved them, and took out the things that didn't work or didn't matter. It was also less difficult, providing a difficult but not frustrating challenge.
About half the fandom believes 3 is even better than 2.
Some fans consider 4 to be the most balanced entry of the NES games, even compared to the above.
Female Robot Masters — more prevalent in fanfiction and fan games than in the actual games, as the only canon ones are Roll (DLN-002) and Splash Woman from 9 (DLN-067) — are commonly referred to as Robot Mistresses.
Fanon Discontinuity: Many fans disregard all the entries not produced in the 8-bit style (meaning 7, 8, and Mega Man & Bass). Some of the more hardcore fans prefer to think that Dr. Wily got fatally crushed in 3 and so ignore everything from 4 onwards.
On the spin-off side of things, Rockman & Forte: Challenger From the Future and both PC entries are often ignored, due to questionable Robot Master designs (most infamously in the former), poorly-written stories (even by the series' standards), and being all-around mediocre games.
Just try to tell some fans that Quint isn't a copy-bot like they insist.
Fridge Brilliance: The Wily Capsule schtick. Just think back to what almost happened to him at the end of 3.
Game Breaker: Beat in 5, where he pursued any and all enemies until they were dead.
So much that he had to be toned down and have his functions changed up in later games.
The Metal Blade in 2; once you acquire it, you can pretty much replace your normal weapon with it. It has lots of ammo (it takes four of them to deplete 1 WP!), and it is one of the few that does notdeny Mega the ability to fire diagonally.
Also, 3's Rush Jet: Due to the mechanics by which it drains energy, you can make it last absurdly long by repeatedly jumping. Plus, unlike later incarnations, you have full control of its position, rather than auto-scrolling.
Bass in 10.
Good Bad Bug: A glitch in earlier games allowed you to make specific enemies * Ones that had a set pattern of movement in which it would move, turn around, move some more, and turn around again disappear by aligning the place where they turned around at the edge of the screen. Very handy with those Goddamn Bats that moved across the ground quickly when you were level with them and were too short to be hit by the peashooter.
In the first Mega Man game, you could use the Elec Beam to repeatedly damage a boss by pausing the game frequently while the beam is in collision. Really handy for getting past the Yellow Devil.
In the NES games, if a weapon took more than one shot to use a unit from the weapon energy bar, you could more or less use it infinitely by pausing between shots.
Hilarious in Hindsight: This scene is from a game that never came out of Japan, depicting Quick Man saving Mega Man's life by taking a shuriken in the back; later in Japan, nearly the exact same thing happens in the first issue of Naruto. What makes this even more hilarious is that Quick Man died from some relatively small shuriken, while Iruka survived a really big one in his spine.
Proto Man is voiced by Ryotaro Okiayu from 8 onwards. What makes it funny is that this was the same seiyuu that voiced Zero in the X series, when there was a prevalent fan theory in the old days that Proto Man is Zero.
Thanks to One Steve Limit by issue of Dub Name Change, fans used to speculate that Drs. Wily and Weil are one and the same person. Now, with the most recent Classic games, the developers are trying hard to make sure that Wily is characterized a lot differently from Weil.
Remember that crappy Mega Man III DOS game? Well, three of the six robot masters are named Oil Man, Wave Man and Blade Man.
Holy Shit Quotient: Bass's ending in The Power Fighters 2; Wily gloats to Bass about a robot he's working on that will surpass Bass and destroy Mega Man, and lowers the blueprints for Bass to see. It's Zero.
It Was His Sled: "Who is Proto Man again?" If you're asking yourself that, why are you on this page in the first place?
Mis-blamed: A lot of fans chastise Capcom for "running out of ideas" for later Robot Masters, without knowing that Capcom didn't make most of them. They're fan designs. If the fans have anyone to blame for the odd Robot Master choices, it's themselves.
But Capcom's still to blame in some degree. They choose the designs, so they could have chosen better ones, or polish a bit the ones they end picking up.
Most Annoying Sound: The soundtrack for the Game Boy version of Mega Man II suffers from excruciatingly high-pitched instrumentation in just about all of the background music. It's proven to be a popular subject for remixes over the years, and most of these have actually been very well-received by fans, with the common consensus being that while the game's composer might have known what he was doing from a musical standpoint, he did an absolutely terrible job of executing it.
Porting Disaster: The images featured in the ending credits of the seventh game were missing in all three versions of Anniversary Collection because the developers (Atomic Planet) couldn't figure out how to properly emulate the Mode-7 features of the SNES. The GameCube version of Anniversary Collection also received flak for switching the shoot and jump buttons. Regardless, the ports of these games are still very playable, and it was nice to not have the music get muddled by certain sound effects, as well as removing the sprite flickering. Having an actual save feature while keeping the password feature for the first seven games was also appreciated.
The GBA port of & Bass made Bass's dash far more difficult to perform due to the lack of a dedicated dash button.
The European version of 4 was rendered near-unplayable due to severe PAL slowdown. The Virtual Console re-release fixes it somewhat, but it can still be noticeable when there are a lot of enemies on the screen.
There's also the Rockman Complete Works versions of MM1-4 available on PSN's "PS1 Classics." Nothing was translated, so good luck navigating the menus or enjoying all of the bonus content if you can't read Japanese!
Rescued from the Scrappy Heap: When first unveiled, Sheep Man was widely hated due to being seen as dumb and overly-childish. However after the game came out, he ended up becoming quite popular due to his powers, stage design, and Narm Charm factor.
Rooting for the Empire: Due to their distinctive designs and personalities, many fans find the Robot Masters more likable and interesting than Mega Man.
Scrappy Mechanic: Or rather the Scrappy Mechanic being the lack of a mechanic. Some complaints against 9 and 10 are leveled at the lack of the slide and charge shot mechanics to make the games more like series darling Mega Man 2.
That One Attack: Wily's final form in 7 probably wouldn't have his That One Boss status if it wasn't for that damn quadruple homing shot that required either pure luck or superhuman reflexes to dodge.
The Scrappy: Back in the day, if there's was ever a Robot Master that was cited as an example that Capcom needs to stop making Mega Man games, it was usually Dust Man.
The second Game Boy game: Doctor Wily stole a time machine, travels thirty years into the future, and kidnaps the future Mega Man, and reprograms him to a Mega Man killer named Quint. What does this brilliant paradox-causing plan amount to? His boss fight consists of him jumping around on a pogo stick/jackhammer. With no given explanation as to what happens after you defeat him, although he shows up briefly with the rest of the Killers in V. Although there is some good fan fiction speculating on whether this is an alternate timeline that was changed, or part of what caused all the Classic characters to disappear for the X timeline.
Navi Mode in the 3 & 4 remakes. Not so much the concept, but rather the execution. The beings used as Mission Control for those two games each induce a Late Arrival Spoiler. Proto Man in 3, who you fight on 4 occasions, and Kalinka in 4, who's been kidnapped. How'd she get to the radio room? Though it's kind of hard to have someone different in 4due to the fact that Proto was rescuing Kalinka. The only option left would be Roll reprising from 2. But what makes Navi Mode in 3 a wasted feature is the person that could've been Mission Control. None other than the supposedly-reformed Dr. Albert Wily. Phase 1: He genuinely wants to secure the crystals, but his robots have secured them. Still, it's better to side with Mega Man here to keep Dr. Light's trust. Phase 2: With his 2nd batch stalling Mega Man, he still gives helpful messages to stall for time while he personally secures the crystals. Phase 3: Now that the plot is ripe, Dr. Wily could engage in Evil Gloating due to the fact that he still has Mega Man's comm frequency... and perhaps a key distraction here and there...
Mega Man 3, Mega Man V, and Mega Man 8 all introduce some level of alien involvement or presence, however the series never expands on this, and in fact, that there were and are alien robots in the universe is completely forgotten by the time Mega Man X and beyond came along.
Uncanny Valley: As a general rule, Mega Man does not look good when realistically rendered, but since laughably ugly boxarts quickly became a beloved series tradition, Capcom has naturally rendered him so for kicks a good number of times. One "classic" example.◊
To be fair, at least Mega Man art is funny-ugly, not scary-ugly as most Uncanny Valley examples are. And seriously, how can you not laugh at Mega Man smiling mischievously while shooting out an enemy's genitals?
Then again, Capcom does need to consider effects on sales when designing boxes. You can find genuine Nightmare Fuel in certain fanart. You need to register to see that; there is no known way to unsee it.