In the ten years since the Marvel Cinematic Universe (MCU) began with 2008's Iron Man, the studios have brought us countless superheroes, which they have finally brought together for one wildly ambitious movie.

Following the events of Captain America: Civil War, the Avengers are divided but must patch up their differences with the arrival of Thanos (Josh Brolin, via motion capture) who is hunting for the six Infinity Stones - jewels which will give him the ability to control everything and follow through on his plans to rebalance the universe by killing off half its population.

Thanos is the most formidable villain the Avengers have come up against so they need reinforcements in the form of the Black Panther team in Wakanda to stop Thanos getting the Mind Stone, which is built into the forehead of Vision (Paul Bettany).

Doctor Strange (Benedict Cumberbatch) also needs to be protected as he holds the Time Stone, and his storyline ends up in space with some Avengers and the Guardians of the Glaxy crew, who are also determined to stop Thanos, aka Gamora (Zoe Saldana) and Nebula's (Karen Gillan) estranged dad.

There are so many characters and storylines to weave together in one film, and somehow the Russo Brothers and writers Christopher Markus and Stephen McFeely manage to make it work and create new character interactions and team-ups which make sense and are a lot of fun.

The film is two and a half hours but it doesn't feel that long as it rattles through plot points, jumps from team to team, and the pace never really dips. It takes a while to get going because it has so many characters and scenarios to set up but it is always entertaining. However, things shift up a gear halfway through and the action gets more creative and thrilling and the stakes become higher and more emotional.

Thanos is the first well-rounded villain Marvel has given fans in some time. He feels deeply, is affected by loss and truly believes his goal is the best thing for the universe. Brolin does an excellent job giving him some depth and he holds the film together.

Other highlights include Chris Hemsworth as Thor, the superhero who gets the most to do in terms of emotion, action and laughs. Drax (Dave Bautista), Mantis (Pom Klementieff) and Spider-Man (Tom Holland) are the most effective comedy players, although everyone gets solid quips and one-liners, Marvel's speciality.

There are some extraordinary fight sequences too, and the standouts in that department include Captain America (Chris Evans), Black Widow (Karen Gillan), Okoye (Danai Gurira) and Scarlet Witch (Elizabeth Olsen).

Robert Downey Jr. does his usual Tony Stark/Iron Man shtick, but it feels a little tired, and Star-Lord's (Chris Pratt) jokes didn't always land, and some characters were better served than others, but that's to be expected in a movie as massive as this.

Given the scale of the film, it is over-stuffed and quite overwhelming, as there is a lot to take in. However, it is impressive the creative team managed to do such a good job juggling so many moving parts. By the end it's clear they have fitted the puzzle pieces together and created an excellent event film that is entertaining, fun and moving at the same time.