Charge Shot is very appreciated, but apart from that, this game is kind of just... okay. I have no idea why they felt the need to make boss HP fill up way slower.

I'll do the same format as my other Mega Man reviews and go game by game.

Toad Man Stage: The water gimmick is okay-ish; I don't like the instant death pits. Other than that, this stage feels shockingly short, and a really... really... REALLY mediocre boss doesn't do it any favors.
Bright Man Stage: I love the brightness/darkness gimmick with the darkness enemies and then having to light the area back up with a firework enemy, super creative stage. The optional pendulum platform section was also a highlight. Bright Man himself isn't too fun to fight; bosses that can just freeze you in place with no real counterplay aren't fun to fight. Fun stage, bad boss.
Pharaoh Man Stage: Love my Egypt, so this stage is... just ok. Sand is an interesting gimmick and the platform enemy section is fine. Pharaoh Man's fight itself is kind of lame if you use the weakness, it's more of a mash test than anything. Kind of a letdown, but at least Pharaoh Shot is a cool ass weapon.
Ring Man Stage: The platforms that disappear are just an okay gimmick, you can kind of tell they didn't have much for Ring Man. The hippo minibosses are a little annoying to deal with but nothing compared to the ring minibosses that are a royal pain in the ass and I honestly just ran into them and skipped them with I-Frames. Ring Man himself is actually a kind of interesting fight, so it's the opposite of Bright Man funnily enough. Bad stage, fun boss.
Dust Man Stage: Interesting stage with the trash presses and the forming platforms, definitely not bad. Dust Man is a pretty fun fight and it's fun to figure him out.
Dive Man Stage: It's a water stage with semi-interesting enemies and the whale miniboss is ok, but it's not really memorable. Dive Man is just like, one step above Toad Man and that's not really saying much.
Drill Man Stage: Interesting aesthetic, but otherwise a kind of boring stage. Drill Man's fight is also not really that good, you're mostly just waiting around until he pops back up to shoot him.
Skull Man Stage: I like the diverging paths in this stage, but that's about it.

Cossack Stage 1: First stage isn't really too memorable, though it is reminiscent of the first Wily Stage in Megaman 2. Boss is cool, love sliding under the boss.
Cossack Stage 2: The Rush Jet part is neat, game gets pretty generous and gives you a lot of free stuff here. The boss is also really cool, and it reminds me of the boss in Megaman 2 that was just the stage. Very nice.
Cossack Stage 3: You can do a funny Wire bug on the autoscroller parts which is fun. Other than that, not a big fan of the autoscroller section, and the boss is just really mediocre.
Cossack Stage 4: Not much to say about this stage. Cossack himself is a fun enough fight.

Alright, onto the Wily Stages.
Wily Stage 1: This stage is full of so many fucking Mets man. There's also a really cheap blind drop into water where there's a set of asshole spikes placed purely to spite the player. Kaizo blocks reappear and are kind of pointless since the player can just use Wire. And oh, the boss of this stage is a giant Met. Thankfully it's pretty easy.
Wily Stage 2: Fun platforming, otherwise not terribly memorable. The boss isn't really great either.
Wily Stage 3: Classic Robot Master rematches. Not much else to say until Wily Machine, where it took me an exorbitant amount of time to figure out I was supposed to hit him with fully charged shots. This fight sucked big time, I'm not going to lie.
Wily Stage 4: From a bad fight to a really fucking hype fight. This is probably my favorite Wily Fight? It's easy but it's so fucking cool and is a great victory lap.

Colorblindness Rating: A
By now, Megaman's menus are no longer confusing for the colorblind with much clearer labels. Thanks, Capcom.

Alright, so starting off with general gameplay changes; pretty much just an improvement on all fronts? The added now-iconic slide changes SO MUCH you can do with the game and makes everything so much unbelievably smoother than Megaman 2 (an already incredibly smooth game to play).

So, I'll be doing the same thing I did in my Megaman 2 Review and go through my experiences stage by stage.
Magnet Man Stage: Not a terrible start, and normally I don't mind the kaizo blocks popping on and out but having to deal with the magnetizing block was actually just kind of awful. As for Magnet Man himself, pretty fun fight; I do think his magnetizing attack lasts a tad too long sometimes, but it adds tension so it's whatevz.
Hard Man Stage: Not too memorable but I do like how some enemies are designed around the slide mechanic, like the Hammer Joes and the monkey enemies that jump around like they're on cocaine. Hard Man himself wasn't a bad fight either.
Top Man Stage: I dunno how this stage relates to Top Man besides the final section before the final boss. Still, pretty fun design and the cat bosses were cute. Top Man himself was kind of a pushover though.
Shadow Man Stage: Now THIS was a fun stage, I love how they play around with the enemies that take away the visibility and the long platforming sections; it's a ton of fun honestly. As for Shadow Man himself, he's fine. I think Top Spin kind of forces you to just get in his face so there's almost no point in learning his attack patterns.

Oh yeah, and I should probably mention Proto Man. Pretty fun fight as long as the ground is either completely flat or shaped like a... |---| stage. I don't know how to describe it. Again, completely love how you're supposed to slide under him when he jumps. The slide is so fucking cool.

Spark Man Stage: Not a terribly memorable stage, but I did like the weird stage hazards on the ceiling and floor that shock you and the conveyor belt platforms.
Snake Man Stage: Awesome stage theme, awesome stage visuals until you go outside for some reason? Not much else to say as at this point. Snake Man himself is decent enough as a boss.
Gemini Man Stage: Super strange visuals but I dig them, I like digging through the bubbles and sliding past. As for Gemini Man, I'm not sure his fight was very fun but at least he went down semi-easy.
Needle Man Stage: Not very memorable sadly. Needle Man is at least fun to fight though.

The Doc Robot fights are pretty similar to how I felt about the original bosses in Megaman 2 with a couple of exceptions.
Heat Doc Robot: Actually much more of a pain. I dunno why he's a lot harder here than in Megaman 2. I think he doesn't do his heat dash very often which is why?
Flash Doc Robot: The arena is AWFUL and I really don't know how you're meant to avoid not running into him. I had to use like 2 E Tanks on this guy alone.
And of course, Air Man came back to haunt me. I HATE AIRMAN SO MUCH

The Proto Man final fight was really cool, if short. I wish he got a healthbar though.

Well, that's that. Onto the Wily Stages.
Stage 1: The stage itself isn't too memorable, but the turtle boss is actually really fun. I was surprised by how I was enjoying myself after slogging through the Doc Robot fights.
Stage 2: Again, not much to say on this one. It's a short ride with Rush Jet. That said, you do get to fight Yellow Devil! I kind of gave up on Megaman 1, so it was nice that I still get to fight him, even if it's not the iconic fight where you have to memorize his pattern.
Stage 3: The darkness enemy comes back! Very fun. I was surprised at how fluid the platforms moved in the final section, definitely a memorable stage just for that alone. At first I was dreading the fight, but then I vaguely remembered something about how the Copy Robot didn't have any I-Frames and that you could supposedly make your Buster Shots do Top Spin damage if you're using Rush Coil swap in the middle of shooting. To my surprise, I actually pulled it off first try and the boss exploded in like 3 seconds. I don't feel bad about it because it seemed like an awful fight anyway.
Stage 4: Boss rematches, good ol' Megaman.
Stage 5: Wily Machine No. 3... is really mediocre?? I spent a good 5 minutes trying to figure out what the hell I was supposed to do until I tried Hard Knuckle and then it became just a really tedious waiting game.
Stage 6: I simply Rush Jet to the top right, popped a couple Hard Knuckles, finished the boss with Top Spin. I'm not sure what the boss is supposed to do, but I'm sure it's a fun boss if you do it legit.

Colorblindness Rating: A-
Again, you can confuse some abilities by the color of the armor if you forget the acronyms, but thankfully you have weapon icons that give you a pretty good indicator as to what they do.
This is a ginormous nitpick honestly, but I think it's still important to think about these things.