It's practically the movie to end all others; the most excitingly-anticipated, over-hyped cinematic event of all time...at least until next year's sequel. But with an age-rating on both sides of the Atlantic that leaves the decision up to parents, is Avengers: Infinity War suitable for the children currently pestering like crazy for a chance to see it?

I'll try to keep this as spoiler-free as possible, but as you may have picked up from the trailer and – unless you've been deliberately living in a sound-proofed room – at least a bit of the hype, this is a pretty dark film. The superhero characters team up to face an impossibly-powerful foe, Thanos, whose masterplan wipes out involving half the souls in the universe in order to bring a measure of interplanetary population control. His quest is to collect the six 'infinity stones' which will grant him the power to commit his awful act of trillion-murder genocide, while the Avengers must do everything they can to stop him.

Along the way, characters die. Early on in its development, the film's producers made it clear that beloved characters would meet their end in the movie, and they've certainly lived up to the promise. For children who have grown attached to favourite superheroes during the first 18 instalments of the Marvel Cinematic Universe, there will be almost inevitably be difficult moments of the Han Solo variety in Infinity War. Which heroes would survive their encounter with Thanos (and which wouldn't) has been a closely-guarded secret, but none of the fan theories will have predicted what actually happens. Suffice to say, most Marvel fans will have something to feel emotional about by the end of the film's 149-minute running time, and some more sensitive children may find the ending itself quite difficult to watch.

There are many other scenes and characters in the film which might be disturbing or upsetting to come children, although for others they'll present no problem. Thanos is supported by a group of particularly nasty-looking minions called the Black Order, and chief henchman Ebony Maw in particular, who looks a little bit like Lord Voldemort and tortures Benedict Cumberbatch's Doctor Strange with a series of suspended glass-like shards, is potentially the stuff of nightmares. Another torture scene, where Karen Gillan's Nebula is placed on a sort of rack and stretched in agony by Thanos, could also be quite upsetting.

For the most part though, the film is standard superhero fare; epic battles and cool stunts abound throughout, and will I'm sure delight older children and young people. There's little bad language apart from a couple of context-required examples, and as usual there's no sexual content. Christian parents won't find anything in there that undermines their faith; the real issue for parents of more sensitive children is simply that ending. It's one of the darkest and most troubling ever seen in a blockbuster movie, although kids should be reassured that with a whole second instalment only a year away, the story probably isn't over just yet. Not even for the characters they might now be mourning...

Martin Saunders is a contributing editor for Christian Today and the deputy CEO of Youthscape. Follow him on Twitter @martinsaunders.