The film centers on Jerry, a cheerful man with a new job in a bathtub factory. He's also insane. Every night at home, he thinks that his dog Bosco and cat Mr. Whiskers are talking to him. When he asks out the company's pretty accountant, Fiona, things take a turn for the darkly humorous. Will Jerry listen to Bosco and take the moral path, or will he listen to Mr Whiskers and succumb to his insanity?
The Voices contains examples of:
- Accidental Murder:
- While driving Fiona back home, Jerry's car collides with a deer. Jerry hallucinates the deer requesting a mercy kill and slits the deer's throat with a knife. Fiona is totally shocked and flees. Jerry runs after her, still holding the knife. She stumbles and falls, and Jerry falls on top of her, accidentally stabbing her in the belly, then kills her to end her suffering.
- To some extent, the case in his second murder. He violently shoves Lisa down to keep her from escaping to report what she's seen, but doesn't appear to have any intention to kill her by doing so. She hits her head on the back of his bed, though, and is slowly dying when he decides to kill her as well. It's only his third murder that is entirely intentional.
- Ax-Crazy: Jerry’s grip on sanity is tenuous at best, and his murderous urges only make matters worse. He eventually turns into a Serial Killer.
- Affably Evil: Jerry really tries to be a good person, but is ultimately unable to control his murderous impulses eventually killing all three of the accounting girls
- All Love Is Unrequited: Fiona's reactions to Jerry's attempts at flirting show clearly that she isn't attracted, and feels annoyed by him. Just as she starts to warm up to him, he crashes into the deer then murders her.
- Alone with the Psycho: Lisa when discovering Jerry's den. Then Jerry comes in...
- Bad People Abuse Animals: Downplayed; Jerry feeds and loves his pets in his hallucinations but their living conditions are disgraceful. When seen through sane eyes, the animals don't seem happy.
- Black Comedy: Jerry's pets talk to him, which is occasionally played for comedy, as is Jerry's social awkwardness. The credits sequence also does a Mood Whiplash play for comedy.
- Blonde, Brunette, Redhead: Lisa, Fiona, and Alison, the three women who work in the accounting department and Jerry's three victims
- Carpet-Rolled Corpse: Jerry rolls Fiona's body into a carpet to transport back to his home.
- Cats Are Mean: Mr. Whiskers constantly belittles Jerry and isn't nice to Bosco. After Fiona's murder, he advises Jerry to dispose of the body, and brags that killing is the thing he likes the most.
- Cloudcuckoolander's Minder:
- Bosco is nice and gives reasonable advice to Jerry. He tries to convince him to go to the police after Fiona's murder. He understood that it was an argument, but the following murders really disappointed him.
- Dr. Warren tries to be this for Jerry, but unfortunately she can't convince him to keep taking his pills (his hallucinations keep him company and enable him to ignore his horrible surroundings).
- Crazy Sane: When Jerry starts taking his pills, he sees the world for how it truly is: his house is a bloody mess, his pets don't talk, and Fiona's head is rotting. He's so freaked out by reality that he immediately flushes his pills.
- Companion Cube: Jerry thinks his pets are talking to him, as well as the severed heads of his victims.
- Creepy Souvenir: In the course of the story, Jerry puts the severed heads of three of the firm's accountants in his fridge: Fiona, then his lover Lisa, and eventually Alison, another of their colleagues. Oh, and he speaks with them, too.
- Dance Party Ending: During the first part of the closing credits, all of the film's deceased characters join Jesus for a colorful dance number in order to let Jerry into the afterlife.
- Dark and Troubled Past: Jerry unsurprisingly had one. He had a mentally ill mother who had hallucinations, which Jerry shared. To stop this, his stepfather tried abusing it out of him. This of course didn't work, and only made him want an escape with them even more. His mother tried to kill herself rather than be committed to an institution, and Jerry ended it at her request. Because the police found him with a bloody knife in his hand, Jerry was locked up (his psychiatrist mentions that he's on parole later).
- Dead Man's Chest: Jerry keeps the heads of his victims in his refrigerator.
- Death Equals Redemption: Discussed.
- Deconstructive Parody:
- Arguably to the comedy subgenre "guy talks with his pets". Jerry is obviously insane, his talks with his pets seem to be hallucinated though the weird ending could mean otherwise, his cat is a sociopath, his home is actually a horrible, filthy den that he usually sees beautiful and clean thanks to his hallucinations, one of his hallucinations starts a succession of disasters, and he eventually becomes a serial killer. The movie is also very funny, thanks to the dialogue with the pets.
- It can also be seen as one towards Garfield, as you have a guy whose name starts with a "J" who owns and talks to his pet cat and dog. The cat is also sociopathic, and treats his owner and the dog poorly while the dog is the Nice Guy of the trio.
- Disposing of a Body: Jerry's method involves sawing bodies into small pieces and storing them in Tupperware. He keeps the heads in the fridge.
- Driven to Suicide: Jerry's mother tried to kill herself when he was a child rather than be put in a mental institution (Jerry then finished her off at her request). Near the end, a distraught Jerry gives up and lets himself die from a gas leak/building on fire rather than harm anyone else.
- Exact Words: Jerry's psychiatrist asks if he hears 'disembodied voices' and he tells her "Not really" because the voices are those of his pets.
- Excrement Statement: Jerry spends the night with Lisa instead of coming home after work. Quite angry at his absence, Mr Whiskers casually mentions that he pooped on the sofa.
- Evil Is Not Well-Lit: Jerry's home looks clean and beautiful when he's off the pills, but when reality hits him it's actually a blood-splattered, dimly lit, full of boxes of god knows what and disorganised shithole
- Formally-Named Pet: Mr. Whiskers, Jerry's cat.
- Gainax Ending: After Jerry dies, Bosco and Mr. Whiskers have a short discussion in a featureless white void about their influence over Jerry's actions. The film ends with Jerry, his parents, the three accountants he murdered, and Jesus performing a song and dance number.
- Good Angel, Bad Angel : Bosco and Mr. Whiskers have this relationship with Jerry. Bosco is the good angel and Mr. Whiskers is the bad. In the end, after Jerry has let himself be poisoned by leaking gas, they comment on Jerry's life in a featureless white plane, suggesting that they're angels.
- Gory Discretion Shot: In the scene when Jerry is sawing Fiona's corpse in small pieces, we only see her legs hanging from the table's edge.
- Hearing Voices: The basic premise of the film. Jerry is a crazy guy who thinks he hears voices from a variety of sources, mostly from his pets, but also from a roadkill deer and the severed heads of his victims. And maybe a goldfish.
- Hope Spot: After Fiona's murder, Jerry's happy relationship with Lisa could have changed his life. Until she enters his home without his consent and sees Fiona's severed head, causing her to freak out, which causes Jerry to freak out, which leads to her accidental death. Then, things really go downhill.
- Insane Equals Violent: Jerry at first just suffers auditory and visual hallucinations. However, once one hallucination starts telling him to kill, he becomes a serial killer. However, he struggles against this aspect of his mind, and hates himself after giving in.
- Killed Offscreen: Alison is the third accountant to die. The last scene she's seen alive, Jerry opens his door after she knocked it. The immediate following scene is Jerry visiting his fridge, in which Alison's head has joined Fiona and Lisa.
- Mercy Kill: Jerry kills the deer, Fiona, and Lisa out of mercy (after having accidentally mortally injured them). He also did this to his mother as a child, at her request.
- Mind Screw: In case you couldn't tell, it's a film about a bathtub factory worker who suffers from a mental illness, talks to his pets, and is eventually driven to murder, complete with talking severed heads.
- My God, What Have I Done?: Jerry genuinely regrets having killed Fiona and Lisa.
- Piss-Take Rap: There's a montage where Fiona, Lisa, and Alison go out for a night of karaoke - Alison is briefly seen performing Ol' Dirty Bastard's "Shimmy Shimmy Ya" (which is actually plot-appropriate, since the song includes the lyric "I go psycho killer, Norman Bates").
- Posthumous Character: Jerry's parents, seen in flashback. Fiona also spends the majority of her screentime as a "talking" severed head.
- The Shrink: Dr Warren, Jerry's therapist, is friendly and tries to be helpful. Unfortunately, her help is very limited, since Jerry won't take his pills. To her credit, she chastises him when he finally confesses he's off his meds. Near the end, he takes her hostage to force her to cure him through an express therapy.
- Trailers Always Spoil: One of the official trailers shows Jerry stabbing Fiona, severed heads kept in the fridge, Fiona's severed head talking, Dr Warren being kidnapped, and the SWAT raiding Jerry's home.
- Through the Eyes of Madness: A major trope of the movie. Jerry hallucinates the voices and sees his home as a clean comfy nest, while it's actually a horribly filthy hole. We see the truth when he momentarily takes medication and when the POV switches to other characters.
- Too Dumb to Live: Allison. After Lisa doesn't show up to work and reading an article about Jerry having been institutionalized as a child after helping his mother kill herself, she decides to go visit him alone. Her head ends up in the fridge with Fiona and Lisa as his last victim.
- Trademark Favourite Food: Jerry's home is full of pizza boxes.
- Uncleanliness Is Next to Ungodliness: When he does take his pills, (or when shown through the eyes of another character), Jerry's home appears to actually be incredibly filthy, littered with trash bags, some animal feces, and pools of blood and splatters from his butchering activities. All this showing how the protagonist is mentally unstable.
- Villain Protagonist : Sort of. Jerry doesn't really have malicious intent, but he is obviously insane and eventually commits three murders and one kidnapping.
- Violent Glaswegian: Mr. Whiskers' lines are pronounced with a Scottish accent, and he's a self-professed killer.
- White Void Room: The ending.
- Off with His Head!: Jerry decapitates his victims and puts their heads in his fridge, where he hallucinates them talking to him.
