Of all the films to be released in 2015, Ant-Man was the one I was most skeptical about. After a tumultuous production which resulted in the exiting of Edgar Wright as director, and the subsequent editing of his script, things were not looking too good for our mini-hero. But Ant-Man has somehow exceeded all expectations to remind us that big things often come in little packages.

A lot of Ant-Man’s success is owed to Paul Rudd who, with a wonderfully charismatic performance, manages to fit into the Marvel Universe with sass, wit, and a great transformation from ex-con to superhero. After being released from jail, he finds himself caught up in a bitter rivalry between Hank Pym (Michael Douglas) and Darren Cross (Corey Stoll). Pym, who was the original Ant-Man, sees potential in Rudd’s Scott Lang and decides to pass the suit along to him to help save the day.

The problem at this point in the Marvel Universe is that all of the films coming out already have the characters established and there aren’t many fresh faces to appear. Ant-Man feels very much like an origin story, and it almost escapes these trappings, but it does tend to have a number of unnaturally imposed moments to explain certain elements that occurred before the film. While these do not diminish the film by any means, they do make it run out of steam by the end of the second act.

Boasting one of the more eclectic casts by Marvel standards, Ant-Man features some great performances from the likes of Douglas, Stoll, Michael Pena and Evangeline Lily. Lily, who plays Hope, Pym’s daughter, has some excellent moments with her father and delivers a killer performance as the daughter who has been continuously snubbed by her own father. Be sure to stick around through the credits for a glimpse at her future in the Marvel Universe. Pena, on the other hand, often steals the show from Rudd while he hilariously delivers some of the funniest lines in the film. He plays Luis, the criminal buddy of Lang who manages to get him caught back up into the life despite Lang’s desire to not have anything to do with it upon his release. The other honorable mention is Stoll, who’s turn as Cross/Yellowjacket, is absolutely menacing and vicious. Unfortunately, for as good of a performance that he gives, his character is entirely unoriginal in his motives which dulls him down quite a bit. If it wasn’t for Stoll, Cross would go down as just another generic super villain with plans for world domination.

The best part of Ant-Man, though, is its fantastically designed action sequences in the ant-sized domains, as well as the Mission Impossible-esque heist scene which serves as the third act of the film. The wildly inventive fight scenes are infused with a mixture of awe and humor as we find our hero fighting inside a briefcase, and throwing Thomas the Tank Engine at his enemies. There is no shortage of innovation in these scenes and the only shame is there couldn’t have been more.

If you told me six months ago that Ant-Man would prove to be one of the funnest adventures of the summer, I would have told you to watch the trailer and tell me that again. But thanks to Rudd, a wonderful script, and brilliant action sequences, Ant-Man can now hold its place as one of the best blockbusters this year. It just goes to show you that size doesn’t always matter.