Diana (Gal Gadot), Princess of Themyscira, travels from the safety of her home to the front lines of World War I to aid American spy Steve Trevor (Chris Pine) and to confront and defeat the war god Ares – whom she believes is responsible for creating the conflict in the first place.

It beggars belief that it has taken 75 years for Wonder Woman to get her own feature film. As one of the oldest and most iconic American comic book heroes one would think she was a natural choice for a big screen treatment, and yet here we are: Diana of Themyscira, making her solo movie debut 66 years after Superman, 51 years after Batman, and eight years after Green Lantern. Hollywood made three films about Blade the vampire hunter before they got to Wonder Woman. They made four Fantastic Four movies, a Catwoman movie, and they even made a film out of Big Hero 6. While it is great that she has finally made it, one does question precisely why it took Warner Bros so long to get around to the task.

Her much-delayed arrival – foreshadowed by an extended cameo in last year’s Batman v Superman: Dawn of Justice – now comes at a critical time for American mainstream cinema. Hollywood is finally making high-budget tentpole pictures based around female protagonists, including the Hunger Games series, the Star Wars films The Force Awakens and Rogue One, and a raft of Disney fairy tale adaptations including Cinderella, Maleficent and Beauty and the Beast. The superhero film, pretty much the most popular screen genre in the world right now, has not shared that approach. Wonder Woman comes to the screen as the first female superhero film since Catwoman back in 2004, and the first to be directed by a woman (I would discount Rachel Talalay’s Tank Girl which, while based on a comic book, does not form a superhero narrative). There is so much cultural pressure on Wonder Woman to succeed that any attempts to criticise it feel unfair and counter-productive.

It is something of a relief, then, to report that in the hands of director Patty Jenkins Wonder Woman is easily one of the most entertaining films of the year, and an absolute knock-out of a superhero movie. It has saved Warner Bros’ expensive DC Comics franchise, which has managed to be financially successful with the likes of Batman v Superman and Suicide Squad but broadly disliked by audiences at the same time. Marketing campaigns and brand awareness can only do so much, and if the DC films are going to succeed in the long term their films simply had to get a lot better. Wonder Woman is absolutely the improvement the studio has needed.

The most significant shift is that of tone. DC Comics kicked off back in the 1930s with the likes of Superman and Batman, and beyond that Wonder Woman, Green Lantern, the Flash, and a host of other characters. They were generally upbeat and optimistic, with the majority of their characters being paragons of virtue and nobility. Recent DC Comics movie adaptations have abandoned that bright optimism and colour with a succession of relatively grim, dour efforts. While it is easy to see the studio executive thinking that led to this – The Dark Knight made an enormous profit, Green Lantern an enormous loss – it has been a poor fit for characters like Superman who have been dragged backwards into Batman’s bleak, miserable outlook. Wonder Woman is a film that reverses this trend, and it is a change well past due. From the opening sequences of the Amazons living in the idyllic paradise of Themyscira to the critical moment of Diana revealed in her superhero costume for the first time – red, blue and cold breaking a landscape of grey – this films points to a new course. I honestly think it is one Warner Bros needs to follow. There has not been a superhero film that felt quite like this since Superman: The Movie.

Speaking of which, Gal Gadot’s performance as Diana absolutely deserves to be ranked alongside the late Christopher Reeve’s as one of superhero cinema’s all-time best. Playing troubled characters is easy. Playing sincerity and simple honesty is much, much harder. She excels at it. She makes the unbelievable not only believable but enormously likeable as well.

The supporting cast is uniformly strong, notably Chris Pine as Steve Trevor and Eugene Brave Rock, Saïd Taghmaoui and Ewen Bremner as his rough band of fellow espionage agents. In the film’s early Themyscira scenes the supporting cast are in a league of their own: Connie Nielsen is dignified and authoritative as Queen Hippolyta, while Robin Wright makes a profoundly memorable impression as her sister (and general) Antiope. Many have described the sheer power of seeing Gal Gadot perform as a female action star. Personally I was much more struck by the Amazons charging the beach in a key early action sequence. Seeing one woman run into a fight has been done many times – albeit not nearly enough times – but seeing several dozen, all powerful and skilled, none sexualised or treated poorly, feels profoundly more impactful. It even manages to naturally include sexual diversity in a mainstream blockbuster without anybody getting in a fluster or losing their head.

Some have commented that the film’s World War I setting is aimed at cynically differentiating the film from Marvel’s Captain America: The First Soldier, which was set during World War II. This disregards the purpose of Wonder Woman’s own setting. World War II had a purpose and a moral imperative. World War I was a global mess of defence treaties leading to pointless mass slaughter. It presents a much more effective contrast with Diana, and speaks to the core theme of the film: can Diana save the human race from war and violence, or are we destined to kill each other regardless?

This is an imperfect film – for one thing it runs a little long, and for another its CGI-filled climax feels somewhat tacked-on – but it still stands head-and-shoulders above every DC Comics film since The Dark Knight. It is easy to get lost in the importance of Wonder Woman – its impact on women watching it, its record-breaking performance for a female director, and the glass ceiling it has smashed – and fail to pause and appreciate just what an overwhelmingly fun adventure it all is. That it is a significant step forward for women in Hollywood is important. That it is one of the most enjoyable films of the year at the same time is just wonderful. This is a great Summer blockbuster: watching it once doesn’t feel like enough, and its best moments are going to be remembered for years.