Breather Boss: Using a Robot Master against the boss weak to them. Copy Robot can also fall under this in some cases, whether it's Guts Man and Oil Man negating their own auxiliary effect (Tremors and oil slicks, respectively), or Bomb Man curiously and Elec Man not-so-curiously only taking 1 damage from anything they get hit with. You'll still have to lay 28 shots to put it down in any case, so it's not a short fight, but compared to the hell described below, Oil Man's Copy Robot in particular is a breeze.
Fanon: It's become fairly popular to depict Mega Man's clone with the scarf from "Mega Man?", to differentiate between the original and clone.
Game Breaker: Mega Man C has all the abilities of the normal Mega Man, in addition to the slide and charge shot. In fact, the charge shot here can break enemy guards at half power and at full power can go through walls. Proto Man subverts this, as his cannon can't rapid fire or shoot through walls, but is just as powerful as the charge shot and hits as a weakness on every Robot Master. And while he takes double the normal damage, Proto Man runs faster and jumps higher than the rest of the cast, and can use his shield to block a few projectiles.
Guts Man, while clunky in the actual stages, is capable of exploiting oversights in the AI for the other Robot Masters, such as trapping Time Man in a box or, even worse, rendering Elec Man completely incapable of harm short of running right into him.
It gets even more ridiculous in the final battle with Dr. Wily. Just build a 2x2 fort (2x3 in the second phase), with Guts Man on the left side of the topmost layer. That will make it next to impossible for Wily to damage you at all.
Good Bad Bugs: There are a couple of glitches in the level construction mode, including a bug that lets you drop through the boss room into the room below, and fight the boss there instead.
Fridge Brilliance: When Proto Man fights his Evil Counterpart, Proto Man's shield doesn't fly away from him when hit, why? He's the one who has the weapon, chances are, he knows how to defend against his own weapon.
Another bit of interest is that when Proto Man fights his counterpart, he shows a dislike of Joes. This is weird, until when you remember that the Joes are based on him. He hates Joes because they're essentially him without freedom!
Time Man's weakness is Thunder Beam. That's weird. What does electricity have to do with time? Fluctuations in electrical current can effect a digital clock's accuracy, and a strong enough surge can force it to reset.
Lethal Joke Weapon: Speedrunners love Oil Slider for its speed and extra jump height, but the average player might have a hard time using it effectively due to the weapon's... unique hitbox.
Never Live It Down: This game attempts to remove the Dumb Muscle image that had been commonly (and wrongly) associated with Guts Man since the Mega Man series. In challenge mode, all his stages are puzzles showing that he can be rather clever.
That One Attack: Wily's version of the Oil Slider. Not only does it shoot a lot of times, but each shot leaves an oil slick that your character will slip on instantly if they even try to walk on them. Also, the game experiences really bad slow down once enough blobs get on screen. All that together means unless you're playing as Mega Man (who can knock Wily out of the attack with a Fire Storm), Fire Man (same reason as Mega), Guts Man (who can block the blobs with a well-placed block), or Oil Man (who at least doesn't slip on oil), your chances of winning can depend a good deal on how often he uses this attack. And if you're Elec Man, you're screwed.
That One Boss: Well, it's not really that hard a game, certainly easier than the original, but certain Robot/Boss combinations are aggravatingly difficult. For instance:
Fighting Fire Man as Oil Man is one of the worst among these, given Oil Man's already-nearly-useless weapon and Fire Man's relative unpredictability (compared to other Robot Masters). On Hard Mode this takes the crown undisputed for the most vicious boss in the game with how quickly he can annihilate you, and how harsh the fire wave, which he LOVES to spam, is. It even has the effect of turning Wily Castle 3 into the harshest stage in the game as well, considering you have not only the devil himself to deal with, but seven other very real threats, with the only consolation being that Oil Man's Copy Robot fight is among the easiest, even on Hard, since the main threat is nullified with his ability to walk over oil puddles and not slip. Take all the lives you can and pray, or you will burn, or even worse, beat Fire Man only to wipe out dealing with the rest of them. It's a nightmare, in short.
Oh, and this means Wily Boss Rush mode is borderline Unwinnable by Design for Fire Man, as he has no means of re-igniting himself afterwards. And guess which boss comes next? Yeah, good luck beating Wily with the de-powered Fire Storm.
The look of the game was given some flak, and the games sales weren't that much, possibly because of the style, so they didn't try out an otherwise impressive remake of the first game, which is sad, more entries could have meant more characters to play as.
Adding the two new Robot Masters.
Three words on the subject as to why we won't see any more of the Powered Up games: Gamers are bastards.
The Scrappy: Ignoring the blackface design of the Japanese version, Oil Man is regularly disliked by players, who hate how impractical and useless his oil-shooting ability is.