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.
YMMV: Mega Man 2
Alternative Character Interpretation: The ending's somber tone causes some to think that Mega Man is plagued with guilt over destroying the Robot Masters for the greater good. This interpretation was explored upon by The Megas in their Mega Man based rock opera.
Anti-Climax Boss: The Wily Alien boss may have had the element of surprise, a gruesome appearance and an awesome background to it's advantage, but it's just way too easy for a pivotal boss fight. It has an insultingly simple attack pattern (fly in a figure 8 pattern and slowly shoot a weak, easily dodgeable pellet for each turn) and it's only weakness is Bubble Lead, the weakest weapon in the entire game, which easily makes short work of it. On top of that, the Alien is a much easier fight than the Wily Machine that precedes it.
Also Wood Man, who has a fairly basic pattern even before you account for the fact that he has more weaknesses than any other boss in the series.
Complacent Gaming Syndrome: Most of the weapons in Mega Man 2 are very good, and the game is generally considered to have one of the better weapon sets. Of course, none of that matters considering the Metal Blade is just that broken. In fact, many players prefer to go after Metal Man first for this very reason.
Crowning Music of Awesome: Virtually ALL of the tracks, but especially Dr. Wily Stage 1 (a.k.a. Okkusenman). This game has more remixed music tracks than any other game in the franchise!
Demonic Spiders: The Sniper Joe mecha-walkers. Giant monstrosities that replace the Giant Eyes from the first game. You're better off running into them to avoid fighting them — unless you have the Leaf Shield, two hits from which will destroy the walker, leaving just a normal Sniper Joe.
Disappointing Last Level: Suffers from this near the end. After clearing the Wily Castle's exciting and challenging first few stages, the 4th stage is where things start to falter. A puzzle stage outfitted with illusion floors and line-guided platforms that, once you figure out how to master it, becomes very tedious. To top it all off, you must fight the Boobeam Trap, which requires ALL the Crash Bomber's weapon energy to defeat with (a fact made worse as the only nearby enemies to item-farm from are Tellies and Sniper Armors). After that comes the series' very first Boss Rush teleport room in the next stage, which doesn't even have a segment giving you the chance to restock your weapon energy beforehand. Meaning that you'll have to fight a battle of attrition with Dr. Wily once the Robot Masters are dealt with. Luckily, the last stage and its boss are far less brutal.
Game Breaker: The Metal Blade. It's a weakness of Bubble Man, Wood Man, Flash Man, Metal Man himself, and the second-to-last boss, not to mention it uses a ludicrously small amount of ammo per shot, meaning it would take a conscious effort to try and deplete it of ammo! Also, unlike any other weapon in the game, this one can be thrown in all eight directions, making it much easier to strike any Goddamned Bats. Plus it can cut through lesser enemies in a row. Oh, and it has a huge shot, making it easy to hit with, especially against enemies that are so small that your normal weapon goes over them.
The Tellys. They're small tube-like bots that infinitely respawn. Again, avoiding them unless you need resources is the best solution.
Pipis. Birds that drop eggs filled with about a dozen tiny birds that Zerg Rush you. The ones in the ladder portion of Crash Man's level are especially annoying, because they're impossible to avoid without the Leaf Shield or Metal Blade.
When the game is paused, Mega Man's vertical speed is set to zero. Repeatedly pausing the game during a long jump will make Mega Man "glide" diagonally instead of falling parabolically, allowing for much longer jumps.
When pausing and unpausing, Mega Man will be in the "teleport" animation for a split second. During this time, Mega Man is invulnerable to all weapons. This glitch is the "Time Barrage" mentioned in the "I can't beat Air Man" song.
If the game is paused while Mega Man is equipped with a weapon that uses less than one bar of weapon energy per shot, unpausing the game will "reset" the bar he's currently on, thus giving potentially infinite weapon energy for those types. This helps make the Metal Blade even more of a Game Breaker than it already is.
One peculiar glitch can be triggered during the Air Man boss battle—if you use Item 1 near the door inside Air Man's room, it takes you to a glitchy, but playable combo of Air Man's stages sprites and the level layout of Skull Castle level 2, but you have to die in it to play the stage, as Air Man's preprogrammed air attacks won't subside without the stage resetting on your death. Unfortunately, it can't be beaten, because the stage boss doesn't show up at the end, forcing you to reset the game, and you can't play the stage without a Game Genie giving you item 1, which is needed to beat Wily Stage 2 and can only be gotten by beating Air Man (and beating him makes it impossible to access the glitch if you replay his stage again, because you automatically teleport out of the beated bosses room upon entry). See it in action here.
Enough objects on the screen animated at once could result in overwhelming the system's RAM, which could result in certain aspects of the game clock slowing down. In particular, a large number of enemies or a sufficiently large enemy could trigger this along with the flickering from Mega Man's Mercy Invincibility and a sufficient number of projectiles on screen. Clever use of the Quick Boomerang (easily the best for shooting many projectiles at once) could result in stretching said Mercy Invincibility much longer than it should ordinarily last. Due to differences in system architecture, this backfires in later rereleases.
It Was His Sled: No, of course Wily isn't actually an alien. The alien form in general counts; back when the game came out it was a huge surprise for obvious reasons, but now it's one of the most famous moments in the franchise's history.
Magnum Opus: For Keiji Inafune, to the Classic series and the franchise as a whole.
Polished Port: The Wily Wars re-release, which gave the game a 16-bit graphical upgrade, remixed music and a save feature.
Scrappy Mechanic: Bubble Lead, due to how useless it is. Except for taking down the final boss of course. Also those god damned disappearing blocks from Heat Man's stage.
Signature Scene: The opening. To the point that anything that is homaging the 8-bit era has a high chance of beginning with an ascending shot of a building with the hero at the top. Even the promotional video for the Mighty No. 9 Kickstarter alludes to it.
The Boobeam Trap at the end of Wily Stage 4. Not only do you have to use Item-1 to reach the higher part of the chamber, but the boss can only be defeated by Crash Bombs, which you only get so many. If you run out, you're fucked.
Not to mention the only way to refill Crash Bomb energy if you run out, would be to shoot hundreds of impossibly placed Tellys and a bunch of Sniper Joes in narrow hallways, in the hope of getting those desperately needed energy capsules...yeah, you're better off killing yourself to restart the stage.
Quick Man's stage is notoriously irritating without the Time Stopper. There are two segments where you have to outrun a batch of instant kill lasers coming out of the wall, and there is very little room for error. And after all that is a few respawning Armor Joes waiting ahead of you.
Heat Man's stage becomes this during the Dissapearing Blocks segment, unless you happen to have Item 2 on hand. Otherwise, you better have split second reflexes and know the exceedingly long block pattern, because one slip up will send you to your death. It makes Ice Man and Guts Man's stages look like warmups in contrast!
Among the Wily Castle stages, stage 4 easily qualifies due to its tedious string of fall-through floors and line-guided platforms, combined with constantly respawning enemies from all directions. The Boobeam Trap being at the end doesn't help matters.