"Hope Rides Alone" starts the rock opera by telling the rise and fall of Protoman, starting with a record player and mellow acoustic guitar and ending with facemelting rock.
"Funeral For a Son" is the only instrumental on the first album, and it's very somber, with synthesizer and a marching drumbeat before a burst of trumpets and bass gives it more life.
"Unrest in the House of Light" has a very different tone than any other song on the album, being a country-style song as Dr. Light tells Megaman his brother's story and how he can't risk him following the same path.
"The Will of One". Megaman defies Dr. Light and goes to learn the truth about his brother and the City, and sets off to fight Wily. As he visits Protoman's gravesite, he reads a message carved there: "Hope Rides Alone." With renewed energy, determined to finish what his brother started, he heads to the fortress. A crowd follows. As Wily's loudspeakers begin to chant the mantra, determined to quiet them, they throw the words right back as a battle cry.
"Vengeance", with Megaman tearing through the robot army like it's nothing while screaming at them to fight better. It also has one of the most tense guitar riffs of all time.
"The Stand" marks Protoman's dramatic reappearance with epic piano and drums, with the drumline at the end repeating just enough to get you pumped up while not so many times as to become wearisome. Special moment goes to when, in-story, Protoman descends the stairs of the caste and destroys his own robots with every crash of cymbals. Not to mention some of the most powerful lyrics ever. It makes a statement about society itself and how we'd rather wait for a hero than be one.
"The Sons of Fate" is the climax of Act I, and it shows. Megaman and Protoman argue to a desperate-sounding guitar before the chorus comes back for the first time since "The Will of One," and the entire song has an edge of hope tinged with sorrow.
"Due Vendetta" is a break from the epic story to call out the names of the Megaman bosses to a chiptune rock song. And it's awesome.
"The Intermission" is an instrumental guitar piece that's only a minute long. It still conveys tons of emotion.
"The Good Doctor" is a duet between Dr. Light and Dr. Wily that decides the fate of the entire City. Bonus points for it being the first time we hear Wily speak in canon; in Act I he had no lines.
"Father of Death" is one of the signature songs of Act II, and it has Light immediately regretting what he's done, Wily killing Emily Stanton after she rejects him, and Light being framed for the murder, all to an epic acoustic and electric guitar piece.
Dr. Wily's Villain Song, "The Hounds". There is no better way to take over the City than with swing and jazz.
"The State Vs. Thomas Light" is easily the saddest song of Act II, and it's so emotionally affecting that the Protomen rarely perform it in full live due to how much it gets to them. The entire song is Light feeling the entire situation is his fault and welcoming death to the point that he refuses to believe it when he's found not guilty.
"Give Us the Rope" is a terrifying Crowd Song. While Light has been found innocent, the citizens disagree, and they try to kill him. And as he escapes, the Intermission theme plays on violin as Light looks over the City that now belongs to Wily.
"How the World Fell Under Darkness" is another instrumental piece that shows, through music, the transition between the Old West-styled City and a City of metal, glass, and wire. It does this by transitioning the style of music, going from orchestra to synth, and ending with the sound of a heartbeat as the synthesizer fades out.
"Breaking Out" is our introduction to Joe, who one day decides he's tired of the City and yearns for the world outside. He conveys his frustration through a rock song even as the citizens tell him to turn back for his own sake.
"Keep Quiet". Joe goes toe to toe with an armed assassination robot in hand to hand combat and comes out on top, only to have Light deliver the finishing blow. He does this to an epic rock song and screaming at it how he's not afraid of death.
"Light up The Night". Joe and Light plan their assault on Wily's tower to an awesome 80's-inspired tune. The entire song is full of hope and energy and light.
"The Fall" is a partial instrumental piece as Joe ascends Wily's tower, climbing higher and higher so he can take it down. The entire piece is filled with an air of hope and imminent triumph which just plain deflates at the very end, as Joe fails to escape in time, is flung off the roof by the explosion, and dies.
"Here Comes the Arm" is the finale to Act II, and it begins on a hopeless note as Light realizes that he and Joe only made things worse. He finally reads the letter Emily had written for him before she died, and the entire tone of the song changes to something hopeful as she tells him to never give up because the City needs him. It ends by transitioning to the same type of music heard at the beginning of Act I.
The Act III trackpreview at PAX 2012, with the female lead being determined to save the City somehow.
The Queen cover CD. All of it, with special mention going to "Death on Two Legs", "Flash", and "Bohemian Rhapsody". The class they show in their cover of "Killer Queen" is breathtaking.
"Beard's Going Nowhere". It quickly goes from an "I Want" Song/Silly Love Song to Dr. Light using his beard to fly into space with his lover.
The early demos of "Father of Death" and "Breaking Out," which in some cases sound just as good as if not better than the final versions.
The cover of "No Easy Way Out" from Rocky IV sounds almost like an entirely different song.
The covers of "Silent Running" by Mike and the Mechanics, which often blend seamlessly into "Breaking Out". The Protomen take the original song's synth and drums and pare it down to just piano, violins, and Panther's voice.
The Built to Last preview at PAX 2013. It was later revealed to be part of two official Mega Man tribute albums.
The Cover Up version of "Mr. Roboto" is even better than the original by Styx - largely via the ham factor being turned up about five notches and recasting the irritatingly chirpy background chorus of the original with a more apt-to-the-setting mechanical voice.