Mega Man 3/YMMV

Accidental Innuendo: Poor Hard Man. Poor, poor Hard Man. His name has made him the butt of many a boner joke for years, and they're unlikely to stop anytime soon. And if that wasn't bad enough, the guy's signature weapon is a giant fist. As in, he fists people to death.
Anticlimax Boss: Despite the ominous buildup to its appearance, the plethora of healing items outside its room, and the fact that it's a giant freaking robot, Gamma is insultingly easy. Its attacks are slow and telegraphed so heavily that a blind man could dodge them, and to finish it off? Pop a single top spin. Bam: Wily's defeated and the day is saved.
- Being The Rival, you'd expect Proto Man to put up a better fight than he actually does. But even when he becomes Break Man (which unused sprites indicate was conceived as his Super Mode), he never deviates from his easily exploited "Hop and shoot in a straight line" attack pattern and will never hit you if you're even the slightest bit aware of your surroundings.
Awesome Music: The title screen theme and the ending/Proto Man's theme are especially popular.
Breather Boss: Top Man has a very basic pattern that he never breaks away from, same with Snake Man. Assuming you don't do them first, they can serve as a good pick-me-up between nightmarish bosses like Shadow Man and Needle Man.
- Among the Doc Robots, Doc Metal and Doc Heat are the easiest if only for the fact that their patterns are easy to follow and don't deviate from their Robot Master counterparts in the slightest, while the rest have been considerably beefed up. If you know about the Rush Jet/Marine trick, you can also take Doc Bubble and break him over your knee by turning him into a helpless sap that doesn't even bother to fight back.
Contested Sequel: While it has plenty of fans that consider it to be the Even Better Sequel to 2, there are just as many players who don't think quite so highly of it. It's a very Obvious Beta with a somewhat sloppy presentation and a difficulty curve that borders on schizophrenic. While the weapons are generally better than 2's, they haven't improved by too much and there are some real obvious stinkers on par with the worst weapons in 2.
Ensemble Darkhorse: Proto Man, one of the most popular characters in the series, debuted in this game. Shadow Man also gets lots of love for being a badass ninja with a powerful and dependable weapon.
Even Better Sequel: For some this game is even better than 2, with its fans citing things like the challenge, improved weapon pool, and level design as factors. It helps that series mainstays Rush and Proto Man were introduced here.
Game Breaker: The Rush Jet is easily the best utility item in any of the games. It freely travels in any direction at top speed, you can conserve its ammo by jumping, and can bypass many tricky stage hazards with it thanks to its large ammo pool. With proper knowledge of how to exploit this thing, the Needle Man revisit is a walk in the park.
Goddamned Boss: Wily Machine 3 becomes unbearably annoying during the second phase of its fight. It spends a lot of time invincible while peppering you with bullets that need precise timing to dodge and opens itself up for a counterattack for maybe a couple of seconds. And since you may very well use up those precious seconds staying away from the shots, this boss can take a good long time.
Good Bad Bugs:
- If one has the Shadow Blade, one can press right to switch over to the Rush Jet (even if they don't have it yet), fill it with energy, and be able to use it before beating Needle Man. You can also use this trick with the Spark Shock to get the Rush Marine early.
- In the Japanese version, the fight against the Flash Man Doc Robot is made easier as it cancels the Time Stopper as soon as it fires just one shot, sparing you the continuous stream it's supposed to fire. Sadly, this was changed in the Western release.
It Was His Sled: While a decent plot twist during the game's debut, Proto Man being Dr. Light's first robot and Mega Man's Aloof Big Brother is the epitome of common knowledge.
Most Annoying Sound: The high-pitched clang the Bolton and Nutton make when they connect, though the annoyance stems from the fact that they're very annoying enemies that love to get in the way since the sound is otherwise well-mixed and brief.
Scrappy Mechanic: Better hope you don't miss with Gemini Laser, because until the laser stops bouncing around, you can't fire another laser or even pause the goddamned game. Thankfully, if it hits an enemy it does hit hard to make up for the trouble it can potentially cause.
- All it takes is one poorly-timed attack for the Top Spin to guzzle up all its ammo in one go, because its ammo consumption is tied to how long its actively hurting an enemy. Better hope you don't misuse it against Shadow Man, because it's the weapon he's weak to!
- Rush Marine isn't bad per se, but outclassed by the Rush Jet in every respect since it can do everything the Rush Marine does out of or even in water, and while using less ammo to boot.
- Surprise Boxes are always nice to find... until they give you a tiny health or ammo pickup that you don't need. Expect that to happen a lot due to their fully randomized item loadouts.
Scrappy Weapon: Perhaps as a consequence of the game's Obvious Beta status, the Spark Shock manages to be a downgrade from the weapon it was inspired by, the Ice Slasher. When you paralyze an enemy, you can't fire another Spark Shock until you've scrolled the paralyzed enemy off-screen, and you can't even switch weapons to kill said paralyzed enemy because it prevents you from pausing, something the Ice Slasher didn't do. Unsurprisingly, many Mega Man fans consider it to be one of, if not the worst weapon in the series.
That One Boss:
- Needle Man's a total spaz who runs and hops around the battlefield like a crackhead, firing off his Needle Cannon in crazy Rambo-style bursts. He's like if Quick Man had the durability and hitbox of Guts Man, which is a horrifying combination to be sure.
- Shadow Man requires some seriously insane reflexes to beat, because you won't know if he's going to slide into you or throw his Shadow Blades until the very second he attacks. You basically have to dodge and hope you reacted correctly, turning the fight into a borderline Luck-Based Mission.
- Oh dear god, the Doc Robots. These guys are basically Mega Man 2's bosses on steroids: stand out examples being Doc Quick, Doc Flash, Doc Air, and Doc Wood.
- The Yellow Devil's back, and he's as annoying as ever. Now he's packing movement patterns that have severe Hitbox Dissonance, and attacking his weak spot is a lot less safe since he shoots more bullets at you. The following Wily boss, the Holographic Mega Mans, can also be a hair-puller if you don't take out the real one before he and his decoys change places. Once you lose track of him you're unlikely to ever hit him again, and he and his clones' bullets come out fast.
Vindicated by History: For the longest time, the Top Spin was universally viewed as a terrible weapon with no redeeming qualities and often held up as the example of how NOT to make a Mega Man weapon. However, time would work wonders for its reputation thanks to players actually experimenting with it in-depth, discovering that it's a very potent one-hit kill machine that pulverizes damn near every single enemy in the game while dealing generous damage to a surprising number of bosses. While its reputation hasn't completely recovered, far more people are willing to give it a fair shake and even sing its praises than before.