Copy Mega Man appears to be an original appearance but with the hostile expression on his face, wears a purple scarf much similar to Protoman's, a triangle faced down in his helmet instead of square and his energy is still green, not blue (as seen during the explosion with the pellets coming out). Likewise, he had joined up with Dr. Wily frequently using his evil terms appealing to the Robot Masters made by Dr. Light, and yet Cut Man thinks to become naive that he's arguably a true hero (though he doesn't want to take a bait up with a mad scientist). Before the boss battle, he has a lot of dialogues to each Robot Master and has letter "W" appears under his health bar because he is simply a Copy Robot as you mentioned above.
Copy Mega Man engages the battle by using two attack patterns: shooting and sliding. Then right after losing half of his energy, he will might perform a charged shots as his special attack that counts. Like the other Robot Masters, he can be invincible during the duration of his powerful attack while charging his Mega Buster and he immediately fires at a brief moment. Besides, he always shoots a normal Mega Buster before he begins with a charged attack again.