Lately, I've been rolling over what it was that was so incredible about the audio in Killer 7. The game is deeply uncomforting in its visual style, with moments of often shockingly beautiful environments simultaneously presented with horrendously stylized enemies. The whole game feels like a bad mescaline trip, and although I enjoy playing the game, what really keeps me tuned in is the devious laughter, the scattered electronic ambient noise, and pulsating techno beats which drive the game along. In other words, the game's visuals fill me with an urge to vomit, but the game's audio gives me a rock hard erection.
In the majority of games, the audio track serves two purposes; it sets an emotional mood
with music and/or sound effects, or it provides momentary tidbits of sound which indicate whether a player has progressed through a challenge (i.e. the harp that plays when you open a chest in Zelda: Ocarina of Time). These little tidbits of audio are somewhat of a reward for the player, as they almost always sound very pretty, and they saturate the player with a feeling of accomplishment. This feeling of accomplishment is critical to keeping a player hooked up to the game.
Killer 7 uses this same format to convey a sense of progress, but the musical choices are intentionally oppressive on the player's ear. Much like the game's visuals, the audio combines unpleasant sounds with really cool video game audio to create something totally bizarre. When you encounter an enemy in Killer 7, you immediately hear a howling, psychotic bit of laughter. The laughter is designed to help you understand that an enemy is close by, so you can stop and find them. The mood of the laughter is hard to pin down, but upon first hearing it, I know that something horrible is out there, and the game designer (the infamous Suda51) intentionally decided not to allow the player to initially see the enemy, which dramatically heightens the tension caused by the demonic laughter. The obfuscation of information is a classic tool for psychological horror and suspense directors like David Lynch and Alfred Hitchcock, and it allows the viewer to apply their subconscious fears on a sound or obscured image, and in Killer 7 I am always expecting the worst when I hear that distant, disturbing laughter.
The game's actual music track is far less jarring, and although the pre-mentioned "puzzle-completion" sound is still in the game, the designers decided that an untuned guitar playing haphazard chords would be more appropriate than a harmonious harp interlude. I mentioned David Lynch a second ago, and he comes to mind again. Killer 7 seems to be one of the first games I've played since Sanitarium on the pc which unabashedly embraced the dark side. It isn't afraid to make you feel unpleasant in order to draw you into the game's world. The game literally makes my girlfriend nauseous when she watches it.
There's other awesome stuff in the game, but I'm not going to go into it, it's definitely worth playing if you're looking for an especially bizarre game.