The Killer Instinct series is well known for its music across all three of its entries, most of them achieving serious earworm status. The original Killer Instinct's soundtrack by Robin Beanland and Graeme Norgate is revered by many as one of the best game soundtracks of all time, to the point where those who purchased the SNES version got a free soundtrack disc under the name "Killer Cuts", but the 2013 title's soundtrack, courtesy of composers Mick Gordon, Atlus Plug, and Celldweller, has gotten its own fair share of praise.
- "The Instinct". There is no better word to describe the main theme of the entire series other than "killer".
- Orchid's theme, "K.I. Feeling", the most instantly-recognizable track on the album.
- "The Way U Move", while used solely in promotions and not actually in-game, is as fondly remembered as the rest of the soundtrack, to the point where it later became the credits theme of the Xbox One game.
- Cinder's theme, "Trailblazer", which could double as the boss music for Eyedol if he was fought on the Lava Bridge stage (the temple had "The Extreme", which also plays at the Lava Bridge on the console version).
- The "Humiliation!" theme. A short, looping, disco-esque track that WILL get trapped in your skull.
Killer Instinct 2
- T.J. Combo's theme, "Feel The Power", is as catchy as they get.Feel the power baby!!!
C to the O to the M-B-O!
- Orchid's theme, "Play Hard", complete with vocals. Real DJs have been known to incorporate it into their sets.
- Gargos' theme. It's so goddamn metal.
Killer Instinct (2013) - Season 1
- Orchid's theme, "Touch Me And I'll Break Your Face", which gives a great callback to her original themes, being poppy and electronic; "K.I. Feeling" even gets pretty heavily sampled during idle periods. The OST version adds more lyrics to the song and an amazing bridge. Features vocals by Ali Edwards.
- The new version of "The Instinct", now more hardcore than ever before.
- Thunder's theme, "Hinnamatoom", is just superb, combining traditional and modern instruments in a way that brings out the best of both. The acoustic guitar part that kicks in during intense moments brings a sense of excitement that's different from the other themes. It's a serious standout among a stellar soundtrack. The OST version also adds the amazing audience choir, recorded by Mick Gordon at PAX Australia, giving even more depth and atmosphere to this theme.
- Spinal's theme, "Warlord", manages to take the spirit of "Ya Ha Haa" and then amp up the creepy factor to high, and there's Ominous Swedish Chanting thrown in to fit with Spinal being the reanimated corpse of a long-dead pirate. It's even more awesome when you consider the "horn" sound used at the start of the theme was created by a Tibetan Kangling, a flute made from a human leg bone.
- Jago's theme, "The Tiger Warrior", now with 100% more throat-singing done by Mick Gordon himself, who actually taught himself how to do so just for this song.
- Fulgore's theme, "Type-03", a hard-driving metal theme with an old-school sci-fi feel thrown into it. It even features a section of his KI2 theme during the medley, along with part of "Full-Bore" as idle music.
- Glacius' theme, "Shatterhail", which also manages to cameo both of his prior themes, and includes a cameo by Maximilian Christiansen as the voice saying "We are controlling transmission."
- Sadira's theme, "Ballet of Death", the creepiest theme on the soundtrack between the screaming and buzzing. The entire track is full with an emotion that can only be described as "dark hatred", fitting for someone who has made a living by taking the lives of others. Features droning, unsettling vocals by Elspeth Eastman that truly fill you with dread and discomfort.
- Sabrewulf's theme, "Lycanthropy". Mick Gordon describes the theme as being akin to Sabrewulf jumping into an orchestra pit and wreaking havoc while the orchestra tries to play around him, giving it a very manic and unhinged feel...up until the end, when it sounds like the surviving orchestra members — bloodied, clawed-up, and traumatized — all gather together and play a haunting rendition of "Tooth and Claw" (the original theme for Sabrewulf) with whatever instruments they have that weren't destroyed.
- The 2014 remix of "The Way U Move" by electronic artist SeamlessR, created for the Season One soundtrack. A stellar update to an already great song.
Killer Instinct (2013) - Season 2
During the process of remastering and rearranging the songs for the official soundtrack release, an accident resulted in Mick Gordon losing a considerable amount of the original material. The result is that several of the OST versions have such notable differences that they can practically be considered remixes. And many of them are considered better than the original game versions.
- T.J. Combo's theme, "I'm Back (To Rise!)", a hard-hitting techno-rap number befitting the more urban atmosphere of his stage. The lyrics depict Combo's rough past which came abruptly to an end, his pride and his desire to prove that he still has his fighting spirit. The rapping is performed by OmegaSparx, who's written and performed songs for past EVO fighting game tournaments. During the idle part an awesome remix of "Feel The Power" kicks in, hitting you right in the face with nostalgia. There's even a few samples of "Feel The Power" and "Yo Check This Out" that pop up as a backing track behind some of the main lyrics. The soundtrack mix features OmegaSparx in some brand-new, gloriously sung chorus verses and even more intense instruments!
- Hisako's theme, "Village of Whispers", an airy melodic tune that you'd expect to hear in a J-horror movie, but accompanied by a slow hard-rock backing track and featuring Japanese lyrics whispered by a very ominous, hoarse-sounding female vocalist. The lyrics, when translated from Japanese, express the undead Hisako's agitated state of mind, with words like "slaughter", "crying", and "grudge" being repeated throughout the piece. During idle portions of the fights, it breaks down into a very quiet, oddly serene mix of the main KI theme that sounds as if it's a lullaby being sung by a chorus of children, very at odds with the rest of the song, reflecting Hisako's life prior to her untimely demise. The OST version makes the vocals more audible and adds more sections not heard in the game version. Also, that lullaby portion? It now has Cry Laughing added to it from Hisako's voice actress. Features vocals sung by Erika Mariko Olsen.
- Cinder's theme "Inferno". It's Cinder's original theme made faster, louder, and more intense, and the end result is something that's updated to match the awesomeness of the other tracks. Some of the guitar work is done by James Mills, aka Little V, a YouTube musician who's done covers of several other KI tracks. The idle part of the theme features quotes from the original announcer and the original Cinder, played over a slow remix of "The Instinct". At 2:16, there's even a short guitar riff sounding very similar to the chorus of "Touch Me And I'll Break Your Face".
- Maya's theme, "Temperance & Vengeance", which is a hard-driving dance-club reboot of her original theme which manages to fit better with her stage. The pulse-pounding beats are accompanied by beautifully-sung lyrics that bring Enya to mind. The OST version makes the techno much more prominent, with the original natural instruments being veiled beneath the new Daft Punk-style synths. Features vocals by Ali Edwards, who previously did the vocals for Orchid's theme.
- Aganos's theme, "Polemos" ("War"), a prog rock piece with heavy Greek chanting in the background by a choir of 461 crowdsourced voices, including the entire Iron Galaxy Studios staff, several from Microsoft, and many others. The dramatic, moving style of the piece is very fitting for a character who has wandered centuries to fulfill its singular task. The OST version has reworked audio mixing and evokes more power.
- Kan-Ra's theme, "Sandstorm", which mixes rock with various string instruments, giving it a Mid-Eastern feel that wouldn't sound out of place in The Mummy (or sounds like what happens if one were to mix traditional belly-dancing music from the Middle East with American 1980s rock music). It's got a sinister-sounding deep electric guitar and odd mystical pad effects, and its repetitive beat is absolutely infectious. The OST version gives the song a much cleaner sound, and adds some more backing instruments to make it sound more fleshed out.
- ARIA's theme, ".execute" is an intense Drum 'n' Bass theme fitting for the Robotic CEO of UltraTech. The idle section, instead of focusing on the traditional part of the Killer Instinct main theme, instead remixes the character select theme from Killer Instinct 1. The OST version turns the entire track into a complete remix of the Killer Instinct main theme, a change which was later reflected in the in-game version.
- Riptor's theme, "Hatchery 09", a sweeping orchestral piece with a primal motif and added electronic effects, befitting Riptor's savage saurian nature. It's also the first direct collaboration between Season 2 composer Mick Gordon and former KI composer Robin Beanland.
- Omen and Shadow Jago's theme, "Herald of Gargos", which is pretty much a heavy metal remix of "The Tiger Warrior". But it's so face-melting your mind will be blown from the sheer intensity, with the chanting being replaced by metal-style screaming of the same lyrics. Even excerpts from Gargos's theme managed to get worked into the main melody, with Jago's KI1 and KI2 themes being sampled during the idle track. The OST version added a brand new intro, new backing riffs, and real drums instead of synthesized ones, making it sound even MORE metal than before. Features death metal vocals by Christopher de Leon.
- There's a hidden track on the Season 2 OST which plays after 2 minutes of silence from the end of "Herald of Gargos" - "The Instinct (Acoustic Version)". Why is it there? Because it's Mick Gordon's parting gift to the fans. He announced shortly after the OST was released that he would not be doing the soundtrack for Season 3.
Killer Instinct (2013) - Season 3
Shortly after that announcement, Iron Galaxy Studios assured that Mick Gordon's role would be filled by very capable hands: Atlas Plug and Celldweller.
- Kim Wu's theme, "The Dragon Spirit", a fast-paced techno-rock remix of her original KI2 theme, incorporating synthesized drums and keyboards, as well as oriental instruments and an actual Korean vocalist singing a traditional lullaby, at first in tune, but then switching to a more punk-ish sound befitting Kim Wu's spunky attitude.
- General RAAM's theme, "For the Horde!", a Djent remix of the Gears of War main theme.
- Rash's theme, "Enter the Battletoad", is a toadally radical Battletoads remix in the style of Van Halen, with some Chiptune flavor sprinkled throughout. The theme is primarily based around the NES title screen theme, but it mixes in the melodies of other stages like Turbo Tunnel and Surf City, with an 8-bit KI theme added in for effect. Idling during gameplay will even trigger an upbeat remix of the infamous Pause theme.
- Gargos's theme, "Kneel to Your God", an up-to-date remix of his original Killer Instinct 2 theme, now even more metal than before. Just like 20 years ago, it's perfectly fitting for a final boss battle, and now sounds like something straight out of Doom. The OST version adds more background ambience, with shrill howling guitars emulating agonized and terrified screaming.
- Mira's theme, "Nocturne in Blood", n eerie mix of gothic opera, orchestra, and techno-rock that sounds like something straight from Castlevania. It carries a heavy air of danger and suspense, but also a sense of refinement and dignity, signifying how Mira relishes her new strength and status as a vampire queen and remembers her inherent training as an ex-huntress.
- Arbiter's theme, "The Champion of Sanghelios", a techno-metal remix of "Impend" from Halo 2 with elements of the Halo Theme added in. Guitars, heavy drums both tribal and techno, strings, and a Gregorian choir with some Sangheili chanting from Celldweller himself come together to form an ancient and epic sounding piece befitting the Arbiter. According to him, the "Sangheili" spoken in the track is actually nothing more than gibberish, which he admits was intentional as he has no clue as to what exactly the Sangheili language entails. In the first Halo game, it's revealed that Sangheili speech is actually reversed English lines, so he was unwittingly right on the money when coming up with the chanting used in the track.
- Tusk's theme, "The Watchman of the Gods", a symphonic metal piece that can be described as "Viking metal", complete with fancy brass orchestra, bombastic drums and a Bulgarian choir. It wouldn't sound too out of place in Skyrim. During the idle portion, the track transitions into a melancholic rendition of Tusk's original theme, fitting his world-weary outlook and thousands of years of living in this world.
- Eyedol's theme, "A Shattered Eyedol", an industrial techno remix of Eyedol's original theme, "The Extreme", which features snippets of the original during the intro. With its 80s horror synths and dark atmosphere it sounds like something out of Hotline Miami and is more than fitting of a Final Boss type character such as Eyedol. Many fans believe it to be Atlus Plug and Celldweller's magnum opus for Season 3.
- Kilgore's theme, "CCIX", combines industrial techno with hints of dubstep and metal. The differences in tempo and instruments compared to Fulgore's theme serves to remind everyone that while Kilgore is the prototype and is in some aspects underdeveloped compared to the enhancements of its successor, it is still dangerous in its own way and should not be underestimated.
- Shin Hisako's theme, simply titled "Shin Hisako", forgoes the horror elements of her original theme in favor of returning to her Japanese roots, mixing in various Japanese instruments in conjunction with dubstep, metal, and redone Japanese lyrics to represent Shin Hisako being freed of the rage and hatred that had consumed her when she was an onryō.
- Eagle's theme, "An Eagle's Call", similar to that of his brother Thunder, combines both traditional and modern instruments while featuring authentic vocals by Native American singers of the Nez Perce tribe to create a triumphant anthem fitting for Eagle's long-awaited debut to Killer Instinct.