It's a bit all over the place to the point it almost feels like three different films that have been tied together. In particular, it takes 50+ minutes before we even really get to the story's central premise, making the first half of the film feel like an absolute drag. Perhaps starting with the marathon and interspersing backstories throughout the run might have been more engaging. As a British & Japanese co-production, it's fascinating to see how the sets of influences blend, and the production is pretty good, with the score being an absolute highlight. Even then, as the end of the film approaches, it takes on more and more of an arthouse feel, with some over-the-top goofball black humour, so some suspension of belief is very much required. It's difficult to give it good scores in most areas, but it was still some damn stupid fun to watch.