What is a underrated film only you know about?

A Scanner Darkly (2006) is a rotoscoped movie based on a Philip K Dick novel set in future LA with a detective trying to find the supply of a dangerous new drug while being addicted to it and suffering from his addiction. The rotoscoping helps add a vibe of delirium to the movie and it is well acted including probably one of the best uses of Keanu Reeves as an actor.
- One of Robert Downey Jr's best roles. He was so detached and horrible in the role while being an absolute goofball (that silencer and the bike). He reminded me of a few tweakers I used to know.
- Checking out more of Richard Linklater's work is also highly recommended.
  Waking Life (2001)
  Philosophy and dreams combine for an enlightening journey. It's a good rewatch if you've not seen it in a long while.
  Before Sunrise (1995), Before Sunset (2004), Before Midnight (2013, I haven't seen this one)
  Ethan Hawke and Julie Delpy have beautiful explorations of love and the human condition.

'Screamers' is a 1995 scifi movie starring Peter Weller. There's just something about the vibe of this movie that really draws me in. If you like sort of bleak mid budget scifi this is a good one.
'Hell Comes To Frogtown', a 1988 movie starring Rowdy Roddy Piper. A post apocalypse where there are frog people and Piper is playing a Mad Max type. It's an absurd fever dream of a movie. 'Big Trouble In Little China' energy.
'Soldier' from 1998 starring Kurt Russell. This is like a forgotten Kurt Russell movie. It's not particularly deep, but it's a good popcorn movie to watch a simple plot of a super soldier taking out evil super soldiers.
'The Spy Who Came In From The Cold' is a 1965 movie. About, of course, a spy. An agent sent not East Germany during the Cold War. It's not the normal action oriented James Bond kind of spy movie. It's a lot talkier, and I find it kind of depressing. So if you like that sort of thing, there it is.
'Observe And Report' is a Seth Rogan movie about being a mall security guard. It is nothing like the awful 'Paul Blart' movies, which everyone assumes when I mention it in real life. This movie is more like Death To Smoochie in its dark comedy sensibilities.
- Man. Screamers was a regular on 10 VHS for $10 holidays. Must've watched Soldier 5 or 6 times on late 90's cable. Watched it not long ago too. Still not great, but I still can't look away.
- Hell Comes to Frogtown is a fantastic movie if you can get over the premise of the movie "the government hires a rapist to help jumpstart the population boom after humanity becomes endangered."

Oscar. It's a comedy set in the 1930s with Sylvester Stallone as a gangster. Directed by John Landis.
Also starting Marisa Tomei, Tim Curry, Don Ameche, Kirk Douglas, Harry Shearer, Kurtwood Smith, Arleen Sorkin.
Trailer:
https://youtu.be/QbfVZBsgC4s
- I've anyways loved that movie!
- Oscar is one of my partner's favourite movies.
  
  The Finucci brothers kill me every time!

I think “Get him to the Greek” isn’t more popular because it was a spin off of “Forgetting Sarah Marshall” which was a better movie IMO.
- Russell Brand didn't age well either

I really like Gladiator (1992) which is an underground boxing film with James Marshal, Cuba Gooding Jr and Brian Dennehy.
James Marshal is a young boxer who’s dad hits hard times and moves to a rough area where he gets dragged into the underground boxing scene.

Arlington Road (1999)
Tim Robbins, Joan Cusack, Jeff Bridges in a taut, pre-9/11 domestic terrorism thriller. I'd pair this with the much better known Denzel Washington film The Siege (1999). Last I checked, this film is not on any streaming platform. Good luck!
Atanarjuat: The Fast Runner (2001)
This Inuit story captivated me. An all-Inuit cast portraying a fable from thousands of years ago. The nearly 3h run time will challenge many. The National Film Board of Canada
Brick (2005)
Fans of Knives Out should really see Rian Johnson's first feature film. Smart and steeped in film noir, with a fantastic and unique script, this flick starring Joseph Gordon-Leavitt.

Dark Star(1974), directed by John Carpenter (The Thing) and written by him and Dan O'Bannon (Alien). Worth a watch for the low-budget effects and realistic depiction of what it must be like to be stuck in a spaceship for 20 years with the same people.
- I tried but gave up after 10 minutes
- Don't forget discussing existentialism with the bomb.

I'd like to nominate two animated French anthologies.
Oggy and the Cockroaches: The Movie (2013)
Based on the TV series, which involves a blue cat, Oggy, trying (and failing) to stop three cockroaches (Joey, Marky, Dee Dee) from eating the food in his fridge. Much like its spiritual predecessor, Tom and Jerry, it's devoid of dialogue. Only this time, it takes place across four time periods: the Stone Age, Medieval Europe, Victorian London (a spoof of Sherlock Holmes) and the very distant future (a spoof of Star Wars). It's got a pretty interesting ending as well (I won't spoil it). If you enjoy silent cartoony humour then I can see you liking this as well, otherwise I wouldn't really bother. (Sidenote: the opening scene is eerily similar to that of the Minions movie, which came out just two years later.)
The Big Bad Fox and Other Tales (2017)
Unlike Oggy, this one has dialogue. I personally watched the UK English dub, which was superb IMO! It's a compilation of three 30-minute specials involving farm animals going on adventures. The first and third ones involve Pig, Rabbit, and Duck trying to fill in for some fantastical deliverer: in the first, they find a stork with a broken wing and try to deliver a baby for him, and in the other, they try to distribute presents because they believe Santa has passed away. The second involves a Fox going to a Wolf and learning to steal chicken eggs and wait for the chicks to grow up, instead of terrorising the adult chickens already in the farm. However, this falls apart when the hatched chicks start calling him "Mummy". Not all of the segments are of equal hilarity (my ranking: 1 and 2 are both great, yet 3 is mid -- maybe I'm just a Grinch), yet it does consistently manage to deliver in terms of its simple yet fun art style, and just the overall charm.
These films aren't exactly the most compelling IMO, but they're good watches when you're lazing and just want to have some cartoony fun.

Kung-Pow: Enter The Fist

creator (1985)
peter o'toole, mariel hemingway, virginia madsen
scientist trying to clone his dead wife, but its really about love and loss and moving on. i just love this movie so much.
fav quote is from it;
"one of these days, vincent, we will look into our microscopes and find ourselves staring into gods eyes and the first one who blinks is going to lose their testicles."

Grabbers
When an island off the coast of Ireland is invaded by bloodsucking aliens, the heroes discover that getting drunk is the only way to survive.
Also The Siege of Jadotville but probab
Irish Commandant Pat Quinlan leads a stand off with troops against French and Belgian Mercenaries in the Congo during the early 1960s.
Not exactly "hidden gem" but definitely not well known.

The Manitou
It's the only horror movie that ever gave me a nightmare, even as a younger kid than I was when I saw it.
My parents were willing to let me watch horror movies pretty young, depending on the exact movie. Like, old school fifties and sixties era horror I was laughing about at 5. So they had gradually loosened the limits up because it never bothered me, nor did I get obsessed.
So we watched this one one night after I picked it out at the video rental place (vhs). It wasn't scary per se, I did way more laughing than anything else because the effects were not impressive.
But the core idea of it, that stuck in my brain apparently, because that night, and a couple after, I had the nightmare of the Manitou growing in me.
I've seen it as an adult a few times, and it isn't exactly a great movie, despite being a fairly classic example of body horror. Decent, not not great, and you have to overlook the era's film making style.
The Wikipedia link
The trailer
I'm not aware of where it might be available, but YouTube has a few clips.
I've never had anyone, online or irl, know that it existed, much less having also watched it.

I don’t like the phrasing ‘only you know about’ because that’s not an easy standard to meet, however I have seen a lot of movies…
The Man From Earth (2007) - College professors discuss many topics with a colleague who claims to be thousands of years old. Fully dialogue driven movie shot almost entirely in one room. Great pacing but just a little cheesy in a few spots.
Cube (1997) - Without remembering how they got there, several strangers awaken in a prison of cubic cells, some of them booby-trapped. Also sort of cheezy but quite engaging and dialogue driven. Oddly enough this one was also shot in one room, sort of.
Suburbia (1983) - An overwhelming sense of despair impels a teenager to leave his suburban home and join up with a group of punk rockers. I highly recommend this movie to anyone who has a soft spot for the punk scene of the early 80s..
SubUrbia (1996) - not as good as the totally unrelated 1983 suburbia, but still pretty good - Five teen friends spend their time hanging out behind a convenience store in a sleepy Texas town. This one really reminds me of my childhood, spending all night smoking cigarettes with friends in the parking lot of a gas station, doing nothing, wasting away life.
I’ll add more if I think of any.
I mostly watch old movies these days (40’s and 50’s) and I have a million of those that I love but it’s kind of hard to judge how obscure they might be. People who watch old movies probably have heard of most of the great old movies I have seen.
- Upvote for the Man from earth. I imagine his situation a lot after this film.

A few I liked that maybe went under a few radars were The Guest, The Dead Don't Die, Brick, and Dave Made A Maze.

OSS 117
A goofy, Zucker-Abrahams-Zucker-adjacent spy spoof from France. Stunningly, the same director and male and female leads wouldater collaborate on 2011's Oscar winning The Artist.

I recently saw this mind bending time travel movie called Primer.
Kidding.
A few indie movies I really like are Ink (2009), Sidewalls (2011), and Cashback (2006). I've linked to some trailers but I hope people just jump feet first without knowing or presuming anything.
Ink is super low budget but it's really one of my all time faves. It starts off sort of like film school assignment early 2000's dystopian scifi fantasy and ends as tear jerker. The full movie is on YT here https://www.youtube.com/watch?v=FIdqnPxfzj0
2022's Vesper was fantastic but I assume a lot of people know this one.
Also, for those looking for some 90s nostalgia, I recently rewatched Singles (1992) for the first time since the nineties and it still holds up.

I was gonna say this Bosnian war film I caught on the public broadcaster 2 decades ago, but it apparently won a fuckin oscar, so I now recommend you watch Birdemic instead.
- Birdemic is a bad movie where everyone does a bad job making it. The only part that makes it somewhat interesting is that it includes obvious wish fulfillment by the writer-director.

Wer früher stirbt ist länger tod (english title: Grave Decisions) is an absolutely incredible movie. It won a ton of awards, but is relatively unknown in the US.
Wiki summary. "The film is about an 11-year-old Bavarian boy (Sebastian Schneider) who feels responsible for his mother's death, who died during his birth, and naively attempts multiple ways to reach immortality (procreation, reincarnation, sanctification, rockstardom) to prevent his tenure in hell."
While this description may sound somewhat dark and serious, it is a light-hearted, inspiring movie with great music, visuals, and proper Bayrisch dialect (I have to use German subtitles to understand any of it).
Side note - if any EU folks here can help a brother out with getting an electronic copy with proper English subtitles, I would be very grateful. I've been wanting to show it to all my friends, but only have a German-subtitled version.

Two good movies my wife and I saw in the last year and we were pretty much the only ones in the theater:
The Last Stop in Yuma County, a tense indie crime movie set almost entirely in an isolated gas station diner. Loads of, "Hey, that's that guy from that thing..." actors in it.
Outlaw Johnny Black, a comedic Western produced, directed, written by, and starring Michael Jai White as a revenge-obsessed outlaw who has to pose as the town's new preacher.

Colin was a zombie movie told from the point of view of the guy turning into a zombie. Made headlines at the time because the guys that created it only spent 220£. I believe it was only shown at a film festive, but crappy copies are to be found online.
I remember liking it at the time, and it has a great ending! Not sure how it would hold up, but I finally found a watchable copy.

Zombie Strippers! (2008) is far better than it has any right to be, especially if they had kept in the deleted scene. The film has Jenna Jameson as a stripper at a club who turns into a sexy zombie, getting a lot of fans in the process. The other strippers as well as others tied to the strip club then have to deal with the consequences as more strippers become zombies to increase their earnings.

Def History of the Occult (Historia De Lo Oculto), an Argentinian sort of supernatural horror/thriller. Came out in 2020, I searched high and low for it, it used to be on Shudder. I couldn’t even find it to torrent it.
Probably fairly well known in Argentina itself, though.