Universally condemned films like The Room and Plan 9 from Outer Space have defied criticism and attracted a loyal cult following. But what distinguishes a truly great bad movie from a just plain terrible one?

There are bad movies, and then there are movies that are so bad, they’re good. That might sound like a contradiction but anyone who has sat through the trash trio of Ed Wood’s Plan 9 from Outer Space (1959), Tommy Wiseau’s The Room (2003), and James Nguyen’s Birdemic: Shock and Terror (2010) will know exactly what I mean.

A lot of movies have been described as “the worst film ever made”, and a lot more will be. But we’re not talking about the Hollywood stinkers that receive Razzie awards – these are scrapings from the very bottom of the cinematic barrel, whose sheer ineptitude in every aspect of filmmaking delights bad movie buffs and consequently turns them into cult classics.

It’s easy to make a bad movie. The Asylum – the indie behind mockbusters like Atlantic Rim, Alien vs. Hunter, and more notably the Sharknado franchise – have turned the practice into an industry. You have to give them credit for those titles, but these manufactured spoofs miss the point of what makes a truly bad film.

Good bad movies aren’t deliberately made, they just kind of happen; the product of a clueless filmmaker’s unwavering belief in their vision. It’s this earnestness, along with a lack of competent moviemaking skills, that provides the crackpot charm, quotable dialogue, and audience participation at late night screenings.

Key ingredients of a great disasterpiece include an erratic and nonsensical plot, a sterile romance, zombified actors, inane dialogue, and much technical incompetence. You can also expect to hear an awful song, which will always be played in its entirety. Interminable mundane scenes will test the limits of your patience, but leave you laughing out loud.

Take The Room, for instance. This romantic drama about a weird guy whose fiancée is in love with his best friend plays out like a bad soap, or a sitcom without a laugh track.

It’s also the narcissistic Tommy Wiseau’s blatant love letter to himself; complete with no less than three egregious sex scenes (scored to equally atrocious songs) that are literal show stoppers.

Birdemic: Shock and Terror kicks things up a notch, with an endless driving scene to pad out the running time, beyond bland leads, and woeful CGI eagles that spit acid and explode on contact. Why? Only writer-director James Nguyen knows for sure. Needless to say, this self-declared master of the “Romantic Thriller™” (yes, the director has trademarked the genre!) is no Hitchcock.

Then there is the loveable Edward D. Wood, Jr., a true visionary that managed to survive beyond a solo feature thanks to a never say die attitude and a knack for securing investors. He was also highly resourceful, splicing in mismatched stock footage and attempting to pass off his chiropractor as the late Bela Lugosi in the aforementioned Plan 9.

There’s no denying that good bad movies are an acquired taste – not everybody gets them.

As with comedy, the appeal depends entirely upon your sense of humour, and ability to appreciate (and tolerate) appalling acting and even worse production values.

If not for their devoted supporters, overcooked turkeys like Plan 9 and The Room would have been found guilty and sentenced to obscurity. Instead, they’re guilty pleasures that are championed by filmmaker fans like Tim Burton and James Franco in the biopics Ed Wood (1994) and The Disaster Artist (2017), respectively.

There’s a delicious irony in that by introducing these rubbish films and their eccentric, deluded auteurs to the masses, it has not only ensured their longevity, but also attracted the kind of attention, critical accolades, and awards that both Wood and Wiseau could only dream about. And that’s a good thing.