- The theme from the trailer of Portal 2, "Reconstructing More Science", just doesn't want to come out from the listener's ears. "It's been a looong time..." The full theme can be heard here. There is another version called "Reconstructing Science".
- The music from the extended co-op trailer is a booming track to emphasise the deadliness of each test our two player robots must endure: "Don't disappoint me..."
- The Part Where He Kills You is basically Portal 2's "4,000 Degrees Kelvin". Plays in one of the tensest moments of the game.
- "I AM NOT A MORON!" starts off as a cheery electronic theme that turns into pure orchestrated awesome. And scariness.
- "You Know Her?" is a fittingly ominous track for GLaDOS waking up, killing Wheatley and throwing you into the incinerator.
- "An Accent Beyond", a fast paced tune that kicks in once Wheatley starts frantically escorting you away from GLaDOS's grasp.
- Bombs for Throwing at You, Wheatley's final boss theme, is like "You Can't Escape, You Know", GLaDOS's final boss theme from the original, except it is faster, more frantic, and has some of Wheatley's Leitmotif mixed in at some points.
- Cave Johnson plays during the teaser trailers, and it's a triumphant-sounding theme that fits the charisma of Cave Johnson proudly displaying various features of the game as Aperture Science products.
- "Don't Do It" is played twice, first during the confrontation with GLaDOS, and again at the analogous spot in the Final Boss battle. What's awesome is how it starts out calm, then grows in intensity at "Please press the Stalemate Resolution Button", and then goes freaking nuts after the Booby Trap goes off.
- With the release of the first volume of the official soundtrack, we now have The Courtesy Call from the opening without the voice over. And it's as awesome as you imagined it would be.
- The Friendly Faith Plate is an has a catchy beat and accompanies the electronic sounds of the Faith Plate sending you careening through the air.
- Vitrification Order, You Are Not Part Of The Control Group and Forwarding The Cause Of Science all count on their own, but they all become even better when you listen to them all together and see how the first two build on each other to create the third, and then combine with another track (Music Of The Spheres) to create The Reunion, arguably one of the best pieces in the game.
- "Music of the Spheres" serves as the leitmotif of Cave Johnson's Aperture. It starts out soft, encapsulating the wonder the player feels looking up at those titanic, abandoned testing spheres. Then, at 1:07, the music peaks, sounding both ominous and suspenseful. What's even more interesting is how "Music of the Spheres" evolves as you progress through Old Aperture. During the '50s chambers, the music starts out with natural instruments, but starting around the '70s, synth starts replacing the instruments, and by the time you get to the '80s, there isn't anything natural left, it's all synthetic. It really gives the impression that something human has turned robotic. Bonus points for the ending of the track sounding more frantic and erratic than usual, mirroring Johnsons descent into insanity.
- Caroline Deleted. Even without knowing the context of the song, you can just feel that something bad is going to happen about half-way through... even though something good happens instead.
- Your Precious Moon, the music that plays when Chell fires the Moon-portal. And yes, it is appropriately awesome.
- Omg, What Has He Done? The first half of the song leaves you feeling terrified at how wrecked Aperture has become... and the second half, a slower reprise of "Wheatley Science", pumps you up in preparation for one hell of a Final Boss battle that places the weight of all of Aperture on your shoulders.
- Spaaaaace: short, incredibly sad for those who finish, and feeling just so empty... And where is Wheatley? Spaaaace... If that didn't make you cry, listen to Space Phase, the menu theme that plays after beating the game. It's a remix of I Made It All Up, but it has elements of Cara Mia Addio and Wheatley's leitmotif mixed in. It sounds so sad and lonely, it's impossible not to feel bad.
- The ending song, "Want You Gone" (spoilers, of course), explains GLaDOS' feelings in song.
- Before the end song, the player is greeted with a choir of turrets.
- "Exile Vilify", by The National is a soothing number which is also kind of sad as it portrays the dilapidated state of Aperture.
- PotatOS Lament. This song only plays on the title screen while you're in the old Aperture Science testing spheres, but it's one of the most haunting, etherial melodies in the entire game. Despite the digital effects and the nigh-incomprehensable lyrics (they're in Latin, for the curious), the sheer emotion in GLaDOS' singing is enough to make you want to shed a tear.
- "GLaDOS's Song", a Cut Song written by Ellen McLain herself with her husband John Patrick Lowrie playing guitar. Here's the original version uploaded by Lowrie, here is a version in GLaDOS's voice, and here is a music video version (with some spoilers). In any case, the song is beautiful and shows that GLaDOS really does have a soft spot for Chell.
- "Wheatley's Song", by Miracle of Sound is a rocker explaining Wheatley in song while also summing up everything he's done.
- "This Is Aperture", a Portal-themed take on "This Is Halloween". Some of the voices in there are so good you'd swear they were the original VAs. note
- Why Wheatley Why? really captures the emotions of most players when Wheatley betrays you.
- Prometheus, despite being just a bunch of audio clips set to techno music, is an oddly majestic sounding piece.
- "Triple Laser Phase", a haunting ambient track.
- Love As A Construct, a beautiful track to accompany a relationship that will never be until the ending.
- There She Is, a gorgeous tune that plays as Chell and Wheatley enter GLaDOS's ruined chamber. It's haunting and even somewhat intimidating, and it fits the scene perfectly.
- Wheatley Science. It's sinister, mischievous, and almost Danny Elfman-like, and hints at just how badly the Enrichment Center is doing under Wheatley's control. Aside from strings and drums, the ENTIRE TRACK is made up of ALARMS. As a menu-screen track, you would hear it when you open up the game in Wheatley's third of the game- so imagine booting up the game, and the first thing you hear is blaring alarms. You KNOW that Aperture is in great danger, and Wheatley doesn't have a clue how to stop it. This is the music of destruction right here.
- Several pieces of brilliant soundtrack are missed simply due to perfect integration during certain contexts; notable examples include synthesized Bach when "flying" and rhythmically whirring lasers when near welders.
- 9999999 is the very first thing you hear upon playing Portal 2 for the first time. The first 1:07 are quiet and mysterious... and then, at 1:08, the full orchestra kicks in, letting the player know that, this time, the stakes are held even higher than they were the previous game.
- Players only get to hear a small snippet of (defun botsbuildbots () (botsbuildbots)) on the main menu during GLaDOS's tests, but the full song truly shows how awesome it is. It recycles a single melody a few times, and each time it does so, it grows in strength until it peaks at 1:53. Combined with the visuals on the main menu of the turret assembly line, the song provides a perfect feeling of Aperture's machinery hard at work, and how it all combines together to form an impossibly large facility.
- 'Hard Sunshine' is a beautiful, melancholy track that kind of gives you the impression of what a Hard Light Bridge is like- imagine walking on sunshine, but not being able to feel the actual sun on your skin...
- Machiavellian Bach. Now that volume's out. Adds all the bits together, for better, um, book-reading. One of Machiavelli's best songs, that, I know, not a moron... Also, He's Playing Classical Music, the electronic version of the song that plays when you're being flung, and the mixture of the two. If you're wondering, this is where it came from.