How do you make a watchable movie out of not just a 44-year old IP that was created purely to sell action figures, but one that was extremely cheesy at the time? The answer is to assemble a cast and crew who completely understand the assignment and hit the daftest elements harder than the Most Powerful Man In The Universe™ punches Skeletor.
We open on the planet Eternia, described in voiceover by Adam (Nicholas Galitzine) as a wonderful place where every myth is real. We get a brief tour of the world, giant tigers, dragons and all then a focus in the young Adam, ten years old and being trained to fight by Duncan (Idris Elba) in the army of Adam's father, King Randor (a heavily bearded James Purefoy).
We soon realise that the narration is actually the now-adult Adam's patter on a disastrous date as he was magically shunted over to Earth, along with the magical Sword of Power to escape the evil Skeletor (Jared Leto). Somehow losing the sword on arrival, he has spent the last 15 years searching for it while holding down a job in Human Resources (the film having a lot of fun with 'HR speak' and he/him pronouns for this self-described He Man).
When he chances upon the sword in a comic book store, the mere fact of him touching it sets off an alarm in Eternia and the evil Beast Man is sent to retrieve it and him. Meanwhile his childhood friend and now badass warrior Teela comes to find him first and take him back home so he can wield the sword and destroy evil.
You can probably fill in a lot of the rest.
What the film does very well is maintain just the right tone, hovering between self-mockery and earnest heroism. Adam is a putz and utterly unprepared for life as a warrior, let alone the Universe's greatest. We learn that the silly names of the characters we may remember from the cartoon or the action figures - Ram Man, the telescopic Mekaneck and, god help us, Fisto - were actually nicknames Adam used for them as a child and, again the film milks the laughs from this fact with ratings-jarring for-the-parents gags such as the deathless line, "Ha! I DO like to fist enemies! Ram Man - GIVE THEM HEAD!"
The for-the-parents element does raise the question of who exactly this film is for. It is obviously a kids movie but the toys it references are unlikely to be known to anyone but their late Gen-X or Millennial parents - possibly why they chose to cast people like Elba, Alison Brie and Morenna Baccarin alongside the younger actors. It is the very definition of a 'who asked for this' film but somehow, it succeeds. Even Jared Leto is alright in it.