Alright, so this game may have started one of the best platforming series ever made, but now that we've got the whole thing laid out on the table, so to speak, it's clear that the first one didn't deliver on that quality. After playing through this, the thing that stands out to me most is that there are very few places where the game combines enemies or hazards effectively. For example...
None of these situations are threatening once you know how to deal with that particular enemy. When you know how Helis behave and are used to shooting as they dive down, you could walk through hundreds more without testing anything more than your patience. The difficulty of these enemies could be increased, of course. One could make the Watchers faster and more numerous, but that would boil down to the same sort of challenge as a rhythm game.
What really makes a platformer shine is by mixing hazards in creative ways. Testing the player's technical ability is all well and good, but there's a limit to how far that can be taken before it gets frustrating. Some games try to test the limits of execution and the people who play them are looking for that, but a well-rounded game has to assume that the player isn't interested in having to make pixel-perfect jumps all the time. Screens like these work well because the hazards aren't difficult on their own, nor are they even that hard to deal with together, but each pulls the player's attention from the others, making them all seem more dangerous than they really are.
That last shot is one of the more effective designs in the game. The player has to jump across small platforms with fire traps on them, which is relatively easy to do when paying attention to the timing, but then Changkeys fly up from the lava to the top of the screen and drift downward. Now the player's attention has been directed upward, and he has to determine what their paths are and move accordingly while also keeping track of the timing on those flame traps, which have just become a secondary concern in his mind. It's important to note that even if none of the Changkeys are heading towards the player, they still offer a threat just by existing, since the player still has to keep track of them and the misdirection could be costly.
I'm not saying this like it's some brilliant move on the designer's part. I only bring it up because this sort of thing is a main component of a good platformer and this game is doing so little of it.
Difficultly can also come from larger, stronger, or more complex enemies, of course. Big Eyes aren't that impressive, as killing them is an exercise in button mashing and there's an element of luck involved when trying to get under them without plenty of space to retreat. More importantly, they require so much precision in fighting them that adding other enemies to the mix would be wildly unfair. Joes and Razys are better examples of a more complex enemy done well, as their behavior is interesting enough to entertain the player by itself for the first couple encounters but could be combined with other minor hazards to spice up the fight, though this game didn't take advantage of that.
In general, the difficulty of this game is all over the place, and the split mostly happens between the enemies and the terrain hazards. Every moving platform is a problem, yet even the last stages throw enemies at you sparingly, as though it doesn't trust that you've figured out how to handle one on its own by now.
Special weapons are helpful in this game, but there's little strategical difference between fire, blades, and electricity. Once you have one of them and can kill Gabyoalls and a few other problematic enemies, it doesn't matter much whether you have the other two. The others are all situational, but ice does get a chance to shine against Big Eyes. I think fire had the best design here, as electricity is far too strong and blades are a bit too slow. The temporary shield was a great idea and I'd like to see more weapons do something like that. Obviously no thought was given to balancing them by energy cost, as the main three all use one bar per shot, while the useless bombs cost two.
Boss fights had their problems too, but the main six did have the range of difficulty and type that works well throughout the series. There's the energetic but easy Bomb Man and Cut Man, the technical challenges of Ice Man and Guts Man, and then there's Fire Man and Elec Man, who will blast your face off in seconds if you don't bring the right weapon or know exactly what you're doing. That's okay. It's good for the difficulty of the bosses to differ since it allows new players to beat at least a couple of them and take the rest out with weapon weaknesses, while veterans could try taking out the harder ones first to spice things up.
My only problem with these is that Elec Man and Fire Man just went too far. I like all three bosses in the Wily stages, though I'll admit that the first could have been toned down just a bit. Wily himself is a terrible disappointment, though after dealing with the previous boss rush I doubt many players would complain about how easy he is the first time.
While the graphics are mostly bland, the game does offer a few interesting things to look at. I like that Ice Man's stage is clearly a tropical area that's been frozen over, and there's something captivating about whatever those things are in Bomb Man's stage. It would have been really cool to fight a few half-built Guts Man soldiers in the last area, but even as they are, they add an intimidating vibe to the place.
While the game is nowhere near as impressive as any other entry in the NES series, it was still pretty decent given the time it was made. We didn't have many platformers back then, and this one had a unique feel to it. Taking weapons from the bosses and using them whenever was a novel idea and was probably what helped it stand out most.
This may sound silly, but if there's one last thing I'm going to complain about, it's this:
Screw you Suzy. You're boring. You are, at best, a decent distraction from more serious threats, but instead you had to keep showing up in rooms all by yourselves and sit around while I gunned you all down. Even in the Wily stages, the best you could do was kinda be in the way now and then, and at that point special weapons made you even more of a joke. Why were there so many of you!?