3 has my favourite track in the series in
Needle Man Stage, composed by Harumi Fujita who also did
Gemini Man Stage and contributed to the staff roll theme. It carries such melancholic pathos that I'm intrinsically drawn to, and she did a lot with that kind of emotive weight in her other works around that time, like
the overworld theme from
Gargoyle's Quest. I always love when a fundamentally silly and lighthearted series like
Mega Man juxtaposes that default state of being with something unexpected that makes the games feel larger than they are. I don't really want or need Needle Man to be characterized literally, as I'm sure he has been in material like comics or whatever else, and this also isn't an angle toward a "Needle Man is a tragic and poignant character in the
Mega Man saga" overread--but the music associated with him gives you something to latch onto regardless, which is these games at their evocative best.
4's kind of tragic to me as several tracks in it are as good as anything else in the series--thinking
Skull Man Stage (percussion),
Pharaoh Man Stage (super-ambitious, hyperactive note and countermelody structure),
Dr. Cossack Stage 2 (really tense drama)--but so much of the rest is uncharacteristically, unpleasantly shrill in instrumentation or downright compositionally inexplicable, like
the password theme. It was Minae Fujii's only contribution to the series and a solo work to boot, until many years later she was among the all-star cast of returning composers doing
10's soundtrack, and
Desert Commando I think exemplifies the best qualities of her past work.