After the Doc Robot stages, we enter a stage titled "Break Man," where we fight a ~mysterious~ robot who fights exactly like Proto Man, with the exception that he is immune to all special weapons. This one's similar to the fight in Hard Man's stage, except we have more room to slide on the upper platform. Beating this automatically moves us to the first Wily stage.
The first section is only guarded by a couple Komasaburos, but the freebies are a little ominous. The E-Tank is actually in a nice spot. It's easy to get, but any player in a hurry might jump before seeing it, or try to jump from the edge of the floor instead of the ladder. With no way back up, they'll be kicking themselves for missing it.
The drop leaves us a little forward from the screen's center, and the camera will stay in that relative position as long as we're moving right. Walking backward fixes it, and touching the wall centers it instantly.
This is the first time we've seen Penpen in water, and their behavior is a bit different. They'll move forward in a sine pattern for a moment before dashing toward Mega Man. Though mildly dangerous on their own, they also serve to distract the player from the spike-covered floor. This stage (and the boss) contain the last water we'll see for the rest of the game, so you might as well take the opportunity to use Rush Marine again while you can. They even leave an energy refill for you.
These green walls are breakable with Hard Knuckle, leading to various goodies. This is another example of the designers providing a situation that looks difficult, but is trivial once players remember they can shoot through walls. They're being exceptionally generous, though. Two lives, E-Tanks, and large health refills, along with a refill for the Knuckle when you're done.
The next screen stands out. We've got one Hammer Joe to deal with and two small holes to slide through, and the Joe is in a good position to knock players into the spikes if they try to get over there without killing him first. He can be taken out from the ladder easily enough, but I like having the option to fight from different elevations on the way there. It's a good setup for a single enemy.
This is followed by two more Joes on level with the player, but the last offers a twist on the one from Hard Man's stage. Though it's possible to stand on the very edge of the platform, we'll want a special weapon or Rush Jet to get past him this time.
Here we get another vanishing block section, with the addition of an easier and rewarding path if we slide from the third block. I'm not sure how a player would even lose the amount of health they're giving us in this stage. One could smash into nearly every enemy along the way and still survive to the refills. Speaking of which, we get two large energy refills before the boss. The first is in a neat position though, in that a player has to use Rush to get to it and switch in mid-air to whatever they want to use it for.
The Kamegoro Maker... makes Kamegoros, which move around the screen diagonally. They drop their shells after a moment, which hang in place and damage Mega Man when touched. They'll also explode when shot, but strangely the explosion itself doesn't deal damage, even though it'll put Mega Man in the "getting hit" state. The Maker itself is invincible, but takes damage when each Kamegoro is killed. There are five in total, and each takes three hits to kill. Each one is also faster than the last. In addition, the walls create small eddies of water that act as platforms and block projectiles.
An interesting side effect of this is that if you stun a Kamegoro, an eddie can knock the stun right off, allowing it to move again. Search Snakes and Shadow Blades kill them in one hit, along with Top Spin, which is by far the easiest option. This is also the last chance to use Rush Marine.
The stage has a couple dangerous moments, but it's extremely easy after what we've already been through and there's nearly as many items lying around as there are enemies. It works well thematically though, as we get a sense of Mega Man sneaking in through the sewers, and in contrast to most sewer levels it's fairly pleasing to the eye. It's just a shame that it isn't pushing the player to do much, especially after the Doc Robot stages. The boss is also easy, but there's a lot going on in the room which keeps it fun to play regardless of the difficulty. I can't say it's a good stage by any means, but it's inoffensive, the boss is memorable, and it's nice to look at.
I found an odd glitch to take advantage of here while making this post. While using Rush Marine, allowing an eddie near the ground to push you into the corner while pressing against it gets Mega Man stuck there. Pausing the game here will remove Rush Marine and leave Mega Man far enough into the wall that he can't be hit, after which you can fire with impunity. Mega Man can walk back out at any time. It's not that useful since the boss is so easy to kill anyway, but it's a glitch I hadn't seen before.