Maybe it's just me, but the re-visit of Shadow Man's domain doesn't seem significantly harder than it was the first time around.
Start by falling down the same shafts you did the last time you came here, only this time the hazard is the spike-lined walls. When you're nearing the bottom, make sure you're not close against the left wall; the floor there has spikes covering it.
When you land at the bottom of the shaft, it should be around three or four strides to the right of the left wall. To your right, you'll see a mechanical rabbit hopping your direction. Take it out with a few arm cannon shots, then hop right and over the bottomless pit there. Next you'll find a ladder, lined by spikes.
Here, it's easy to jump too high and hit a spike because you're slightly off-center. Instead of doing that, make a short hop just high enough that you grab the bottom of the ladder. Now climb straight up it and you won't have to worry about the spikes. Above, one of the suctioned eyes is likely in the way, so hit it with a shadow blade, walk across the ledge it occupied, then climb down the next ladder.
From there, climb down yet another ladder, into a room with one of the giant, stomping robots. Slide under it and drop down the pit on the screen's left side, then head back to the right. You'll find a series of ledges rising up like a staircase. Take out more suctioned eyes and climb to the top, then hop over the gap to the right.
In this area, there's one of the bulbs that makes the room dark. There also are four ledges, red in color. Stepping on these causes them to buckle under your weight, but they're good for quick hops. Hop along them and from the fourth ledge (the highest) jump out to the right as far as you can to land on a new ledge. Walk along and take out any enemy you may encounter, until you find yourself looking over another bottomless pit and a second series of collapsing ledges.
Leap out onto the first, trying to land as far toward the right portion as possible, then hop quickly across those ledges and to safe ground on the opposite side of the black pit. Then proceed right yet again, blasting any robots that get in your way, until you come to a ladder you can descend.
The next room should have some robots you can blast that hopefully will leave behind a few energy pellets. Then you're at the gate to the first Doc Robot encounter.
Doc Robot - Wood Man
This fight is actually quite simple. First, switch to the Needle Cannon. The way Doc Robot attacks now is by throwing a set of four leaves to the ceiling while more leaves encircle him as a shield.
Position yourself so that when the leaves fall, you'll be safe between the first and second leaf, and watch the shield around Doc Robot. When he tosses it, jump over it and start firing your needle cannon. You should get in quite a few hits, around one fourth to a third of his life meter.
The pattern will now repeat. When the leaf shield falls away again, you should have over half the robot's life. Again, he'll throw up more leaves and use the shield. This time, be prepared to slide under him when he throws his shield and hops toward you, then turn to fire needles from behind. Once the leaf shield comes up again, run to the opposite side of the screen (it should be the screen's right side, now), and be prepared for the leaf shield to fall away again so that you can finish the job. The battle is harder than the similar encounter in the original Mega Man 2 cartridge, but still not overly difficult.
With the first Doc Robot encounter out of the way, it's time to head for the second. You'll find a large energy capsule in the next hallway, and beyond that a series of hellish jumps that will likely trip you up the first time you attempt them.
To survive this dangerous crossing, you'll want to equip the shadow blades. As you cross each pit, be prepared to throw a blade in mid-air to take out the parachuting robot, then chuck another as you land so that you take out the rabbit that hops along these ledges. Repeat the pattern all the way across the lava, until you reach the other side.
Now you should encounter a red-capped spring robot that fires magnetic missiles. Take out the robot and its missiles with more shadow blades, then proceed to the second Doc Robot encounter.
Doc Robot - Heat Man
Hopefully, you've still got a decent supply of shadow blades left, because that's the weapon of choice when dealing with this fiend.
As Heat Man, Doc Robot first throws a triple column of fire, then starts to flicker and blazes toward you. He's immune when in this condition, so wait for him to stop before countering with some shadow blade shots. He'll then repeat his pattern, so you'll want to be prepared to go through the necessary motions throughout the remainder of the fight. You may need to use an energy tank near the end.
And so you've tackled three of the four Doc Robot stages, and only one remains. It's time to pay another visit to Needle Man's former abode.
A-1 (blue), A-3 (blue), B-5 (blue), B-6 (red), C-1 (red), D-3 (blue), F-4 (blue)
NEXT: Needle Man Stage