The finale episode of One-Punch Man season 2 ended with Bang, but not with a bang, as the story was left on an odd note. Debuting in Japan in late 2015, One-Punch Man immediately struck a chord with anime fans, while also garnering strong crossover appeal across the world. The adventures of Saitama, a man frustrated by his habit of beating any opponent with a single blow, mixed comedy with gloriously animated fight sequences and added elements that parodied the anime genre to hilarious effect.
After behind-the-scenes turmoil led to an almost four-year delay, One-Punch Man season 2 hasn't enjoyed quite the same rapturous response. This is perhaps partly due to the shift from self-contained stories to a single long arc, and Saitama's subsequent lack of screen time, but the main cause of contention has been lower quality animation. Nevertheless, the anime series remains incredibly popular and there was plenty of anticipation heading into One-Punch Man's season 2 finale.
The concluding episode (titled "Cleaning Up The Disciple's Mess") centers around the reappearance of Elder Centipede, who interrupts the long-awaited clash between Bang and Garou. The giant creature proves too formidable for the assembled collection of heroes, but Saitama eventually arrives to save the day with, you guessed it, one punch. During the melee, Garou is whisked away by the Monster Association, with the villainous group seemingly keen on turning the self-proclaimed "Human Monster" into the genuine article. And that's a wrap for One-Punch Man season 2.
The abrupt ending couldn't be more different to the climax of One-Punch Man's debut season. Season 1 concluded with Saitama's best opponent yet, taking on the undefeated alien invader, Boros, in a scrap for the ages and the fight against Elder Centipede doesn't even come close to that level. Since One-Punch Man's second season has been more focused on long-term stories, the absence of a major final battle can perhaps be forgiven, but the episode also fails to deliver any sort of major plot cliffhanger that builds excitement towards season 3. The closing image of Phoenix Man flying Garou away to the Monster Association is far from a surprising development and manga readers will know that the ramifications of this scene aren't the main focus moving into season 3.
Considered on its own merits, "Cleaning Up The Disciple's Mess" is a strong episode with several standout moments, but it doesn't work as a season finale and many viewers would have tuned in the following week expecting another installment, since none of One-Punch Man season 2's main characters move forward in the finale episode. Garou has escaped Bang's justice once again, the Monster Association remains a mysterious threat in the shadows and Waganma is still being held captive.
One-Punch Man season 2's strange ending is even harder to understand considering the anime only needed to adapt one or two extra manga chapters to deliver a more definitive finale. The episode ends without giving any clear idea on the direction for season 3 but, following Elder Centipede's defeat in the manga, the Heroes Association reveal their plans for a counterattack on Gyoro-Gyoro and his upstart Monster Association and this would've made for a far superior ending.
While one extra episode focusing on the Heroes Association as they plan their assault wouldn't have made for a more action-packed or dramatic finale, it would have at least built anticipation towards season 3 and informed the audience exactly where the story was headed. Instead, One-Punch Man season 2 feels like an unfinished setup to something much bigger.