A fish lies dead, poking its empty face out of a brown, half-empty fish tank. Behind it, the walls are covered with layers of peeling wallpaper. Electrical cables are stuck up with packing tape. Fluorescent lights buzz and flickers. Everything looks brown, or green, or other varying layers of ripe nausea. You cannot see the floor during this slow three-minute opening shot, but I bet real money if you were there it would be moist to the touch.

Hotel Poseidon must surely win some kind of award for its production design, which positively oozes with rot and decay. It forms the setting for Stef Lernous’ truly odd film directorial debut: neither funny enough to be properly classed a comedy nor horrifying enough to be considered horror. It is certainly rich in grotesquerie but we generally do not talk about that as a genre any more. What it definitely counts as is original. It is a warped, surreal comedy of manners inside the worst hotel on Earth.

Dave (Tom Vermeir) inherited the Hotel Poseidon from his late father. Now, while he struggles with a dead relative and a friend wanting to throw a party in the main hall, Dave is forced to contend with Nora (Anneke Sluiters) – the hotel’s first new guest in some time.

With Hotel Poseidon, Lernous has expanded his internationally noted theatre company Abbatoir Fermé from stage to screen with a distinctive and memorable film. You can see Lernous’ theatrical origins in the heightened setting and performances. He keeps everything hermetically sealed, however, in its own aesthetic bubble – this allows the over-the-top delivery and imaginative mise-en-scene to work to the film’s advantage. It boasts a richly imagined, vigorously unpleasant world; one Dave seems unable to leave. There is a decidedly Sartrean vibe here, echoing the philosopher and playwright’s No Exit in its miserable exchanges and claustrophobic sense of confinement. In some respects Dave’s situation is even worse: his hellish encounters get to come and go, but he seems trapped in the hotel indefinitely.

It is a superb film for small, supporting performances, with Tom Vermeir’s meek, hesitant portrayal of Dave providing an effective ‘straight man’ to a succession of odd and absurd acquaintances and relations. Tine Van den Wyngaert and Steve Geerts deserve particular praise for their turn as a singularly offensive pair of funeral directors.

Ultimately it is to the film’s credit that it is so difficult to summarise or categorise. It is less about plot than it is about place, and less about character than tone. If one were to force it into a genre, it is probably slightly more horrific than funny – and fans of more inventive end of screen horror seem more likely to appreciate it than fans of comedy or drama. For many viewers it may seem appallingly self-indulgent, but for a specific audience it may be precisely the sort of distinct and imaginative artistry that they crave the most. It is certainly not the sort of film that one forgets.