The title theme is an upbeat tune that really gives the impression that the Mario Bros. are in for a fun adventure. The Bowser's Minions remix adds several more instruments, giving it much more beat.
The final battle. A grim finale song that really makes it feel like the entire world is at stake. Here's the Bowser's Minions remix. While not quite as intense, it instead makes the original song even more haunting, telling you that Cackletta has had more than enough of you.
Bowser Castle. Such a moody yet atmospheric tune for the dangerous gauntlet that is the game's final dungeon. The remake's version adds some epic violin from Cackletta's theme.
Popple's theme.. A tune so upbeat it's almost impossible not to dance along with it. The fact it's used for Fawful as well as Popple (at least the non-English versions) is just the icing on the cake. The Bowser's Minions version is even used briefly in the cutscene where Captain Goomba's squadron starts their assault on Bowser's Castle.
The boss theme is rather underappreciated compared to the other main boss themes in the series, but it's still quite good.
Shroob Castle. Also, there's Shroobs!, the original theme that "Shroob Castle" is an arrangement of. And as if both arrangements weren't suspenseful enough, the tension is ramped up in "Shroobs!", thanks to its intro.
Fawful Castle, the final dungeon, has a wonderfully haunting piece of music led by a celesta and flute that sounds more like what you might expect in Slippy-Slidey Ice World. Considering what Fawful Castle is, the song really fits the mood nonetheless.
The Cavi Cape theme is particularly noteworthy for using the Dorian mode, an archaic musical scale not even used that often in classical or traditional music, and likely all but unheard of in video game music. The end result is a piece with a very strong emotional neutrality; neither happy, nor dark, nor sad.
Toad Town. It feels just as peaceful and relaxing as the town itself.
The Title Screen wonderfully shows off the more orchestral flavour of the game's music. Extra points for remixing some of the Super Mario RPG battle theme.
The Boss Battle theme starts fairly joyful as per the series' tradition, but then gets incredibly tense and epic. It combines the almost toonish playfulness of before with some no-nonsense transitions. When you consider this is often how elements blend in the Mario & Luigi games as a whole, it's little wonder many claim this the best boss theme of all.
Beneath Pi'illo Castle is also pretty enjoyable even though it plays fairly early in the game. Even more awesome is that at times, the style, timbre, and feel of the piece calls to mind the third movement of Ludwig van Beethoven's famous Fifth Symphony, if you're familiar with that part of it.
Nightmare Lullaby, the "bad things are happening" tune, is creepy, tense, suspenseful, and awesome at the same time.
Dreamy Wakeport Repose. Such a relaxing and soothing song. In fact, one may say it's way too relaxing, but still an awesome and soothing song to listen to. Its real-world counterpart, Shopping in Wakeport, is also pretty relaxing, what with the flute and guitar and all.
The Nightmare Road, the song that plays right before the final battle, gives off the feeling of an epic confrontation.
The Law of Pajamaja qualifies as Funny Music. This song, combined with the BEEFY Massif Bros. and the absurd stories of the Muscle Lords, creates an unbelievably hilarious mood for Mt. Pajamaja.
In the first few battles before Paper Mario appears, there's an awesome remix of Come On!, from Superstar Saga.
The normal battle theme, Mixed-Up Scramble, which replaces "Come On!" after Paper Mario appears, and it's easily one of the best battle themes in the series, if not the best.
The minigame themes:
Do It Now! is an upbeat, adrenaline-filled piano song.
Time's Running Out! is a wonderful, fast-paced action theme for when you're either chasing or running from something.
Where's Toad? helps you slow down and think when you're searching for hidden Paper Toads.
Destination Unknown. Similar to "Where's Toad?", but both a little tenser and a little more laid back at the same time, which is fitting since this usually plays when you're in enemy-filled areas searching out one particular member and have to travel a little farther than for the Paper Toads.
While technically a remix of Partners in Time's song, Prepare Yourself! is often credited as a great remix!
The theme for the warm-up before the final boss battle, Double Bowsers!. It has a massive contrast with the rest of the soundtrack, feeling a lot like "Forze del Male", giving the vibe that the Bowsers aren't joking this time around.
The Final Boss theme (creatively titledFinal Battle) is by far one of the most epic themes in the series, feeling like a hybrid of "The Grand Finale" and "Adventure's End", and easily rivaling them in terms of awesomeness. Not only that, but it also sounds very reminiscent of "Darkness of the Unknown" (particularly at the beginning and especially during the second half).
Whispered Secrets. Quite a beautiful piece of music that plays when Princess Peach first meets her parallel Paper counterpart as well as when said characters are talking about hair styles and clothes while at Mount Brrr.
Big Bang, the regular boss theme, mixes perfectly both Mario & Luigi and Paper Mario tunes. Just like Dream Team's boss theme, it starts playful and full of joy, but becomes dark and tense, just like the game's plot.
Mysterious Bowser's Castle, which is played during the first visit to Bowser's Castle, sounds much more menacing than the usual Bowser's Castle theme, much like the Neo Bowser Castle themes in Dream Team. Of course, this is to show that Bowser is a much more menacing villain now, nailing the atmosphere perfectly. And while it's replaced with the track below for the second visit (as Neo Bowser Castle), this track is reused for the last Papercraft battle with Papercraft Bowser.
Floating Castleof Doom, the final dungeon theme, sounds nothing like a regular Bowser's Castle. Instead of sounding epic and triumphant, it sounds full of despair and agony, perfectly reflecting what will happen if the Bowsers manage to win.
Good-Bye Sadness. For all the game's tear jerking moments, among them our heroes begging the formerly brainwashed Wiggler they just defeated to Please Wake Up, the flashbacks to the Bowser Jrs' budding friendship after their boss battle, and the first part of the Kameks' defeat scene.
Bowser's Coming! is this game's respective remix of Bowser's theme from Bowser's Inside Story. It has a chilling atmosphere that serves to demonstrate how menacing Bowser is.
Forest Fairy Melody is a beautiful and mysterious theme that fits the pretty but eerie Gloomy Woods to a T.
Alternative Title(s):Mario And Luigi Superstar Saga, Mario And Luigi Partners In Time, Mario And Luigi Bowsers Inside Story, Mario And Luigi Dream Team, Mario And Luigi Paper Jam