Meet Junk Golem. Junk Golem drops into the screen when Mega Man gets close, then starts hurling blocks of trash at high speed directly at him.
These can be dodged by sliding or jumping, but they also explode, and the pieces can trap us against the wall if we run back too far. Junk Golem takes six hits, and though Top Spin kills him immediately, the real threat is the blocks and nothing destroys those quickly. Even after killing him, a falling block will keep moving as though he were still there to throw it. In short, Junk Golem is a pain in the ass to deal with.
The next one just gets a platform, but the third appears while we're still falling into the room, and since we're against a wall, jumping over it won't work. The only way I've found to avoid this is to jump immediately after landing so he throws it above you.
Your reward for beating that one is some more junk to the face, as another one shows up in the same room. The last room looks ominous, but nothing happens and we're free to move on to the teleporter room.
This time the boss fights are identical to the first encounters, so there's nothing new to discuss here. For beating them, we get some item rewards and some ominous music before we drop into the fight with Wily.
The first form slowly walks in from the side, and when the gun appears it starts firing spinning shots similar to the last form in the first game, though they spin in the other direction. These can be difficult to deal with since he's also trying to step on you, but it's possible to walk between his feet and slide under the gun.
The gun won't shoot while you're underneath him, and Mega Man can safely jump and shoot when standing near the legs. The gun is the weak point, and it takes continuous damage like the rest of Wily's bosses, so destroying it is easy enough. The Spark Shot takes it out in four hits though, and we're not using it for anything else, so blast away.
In the second form, Wily will lob shots out of the two holes on the sides while smashing the machine down every time both legs have taken a step. These shots are also tough to avoid, and Mega Man now has to run under both legs when moving to the other side or get crushed.
Your strongest weapon here is the Hard Knuckle, but it has to be aimed upwards and Wily can dodge it when he moves down. He's also slightly weak to Search Snake, Magnet Missiles, and Shadow Blades, but magnets won't track him and you'd run into the hitbox more often then not when trying to hit with snakes. Shadow Blades only deal two damage and are slow, and we can only hit with normal shots when he's on the ground. The best option is to just get right in his face with Rush Jet.
Finally, we face off with Gamma. Before he fully activates, we have to deal with a smaller head that acts similar to a New Shotman. He can only fire at set angles and doesn't move, so we're not in much danger in this part of the fight. He's immune to normal shots, and his only weaknesses are the Hard Knuckle and Shadow Blade. We can use Rush to get to the upper platform, after which he'll stick to horizontal shots that are even less of a threat, or we can just fire blades at him from underneath.
Wily then drops in with the top half of Gamma's head, and kindly brings along a new platform for us. Gamma now fires large, faster shots aimed at us, and periodically moves his fist along the ground. The spikes are as much of an instant death as any others in the game, but the hand can be used as a platform to get back up or at least avoid the attack. He can be damaged by snakes, but you'll need to make a tricky jump from the upper platform to hit him without falling off. Top Spin, however, is an instant kill on this thing. Just jump into Wily's bubble while spinning, take the hit, and spin once more to drain all his health. You have to get hit by the cockpit first; Mega Man will just do a little damage and bounce off if he's already invincible.
Gamma explodes, Wily begs for mercy, and Proto Man continues to be mysterious.
Though the Junk Golem is kind of awful, both boss fights ended up working well. The first offers a difficult showdown, and continues Wily's tradition of throwing odd projectiles at us with the new hazard of being stepped on or crushed. Rush Jet trivializes it, but Rush Jet does that to everything. Gamma fits the role of the easy spectacle boss, but he at least takes some experimentation to figure out how to damage at all, and most players are likely to figure out that snakes work before trying Top Spin, putting themselves in danger of falling into the path of a spiky fist.