(Niantic CEO John Hanke talks to disappointed attendees at Saturday's Pokémon Go Chicago event.Niantic)

What was once a simple fictional battle between Ash and Team Rocket has quickly been subsumed by the battle over who's to blame for the failure of the big Pokémon Go event in Chicago.

In a blog post Tuesday, Niantic CEO John Hanke responded to allegations that the game developer had not adequately prepared for Saturday's 20,000 person event which was plagued by technical problems that made the game unplayable for many attendees.

"Last Saturday was not a happy day for us but we are committed to listening to that feedback, however harsh, to improve what we do," Hanke wrote in the post.

"We heard boos and shouts from the crowd," Hanke said, describing the crowd's reaction.

Hanke said that while Niantic did have some server issues, it was mostly inadequate coverage by cellphone providers that led to lagging or inaccessible apps.

What happened? Technical issues with our game software caused client crashes and interfered with gameplay for some users. The gameplay issue was resolved with a server configuration change and the crashes were also addressed for many but not all users. A more protracted problem was caused by oversaturation of the mobile data networks of some network providers. This caused many attendees to be unable to access Pokémon GO or other Internet services. Network congestion also led to a login issue which affected some users able to access the Internet. This latency-related login issue was addressed with a second Niantic configuration change.

On the pure network access issue, we provided detailed estimates on attendance and required data throughput per user to our event partner who worked with the major carriers to allow them to plan for adequate coverage. Some carriers deployed Cellular on Wheels (COWs) to extend their capacity. In other cases the providers deemed them unnecessary based on other infrastructure already in place at the site. Users reported different levels of success with these providers. Wifi was enabled by one provider as a solution which helped some users but not all. Sprint was on site as an official partner, deployed a COW, and their network was busy but held up well. Although many players were able to play normally for the majority of the day, many were not, and based on that we made a number of adjustments to the event plan.

This is the first comment Niantic has made publicly since the event, when Hanke told attendees that they would be refunded their $20 ticket fees, and offered $100 in in-app purchases.