I’d only been at Pokemon Go Fest for five minutes the first time I heard someone shout that an ultra-rare Pokemon was nearby. With 20,000 of the most dedicated Pokemon Go fans from around the world in one spot, it wasn’t surprising to see that people were passionate, and the friendly, cooperative spirit that started the day represented everything great about Pokemon Go and its community.

As players ran past me, I joined them, running toward a 10-foot tall physical PokeStop and excited for my first chance to catch an Unown, one of the rarest Pokemon in the game. People were laughing, the weather was great, and everyone had a smile on their face. As I got closer to where the crowd was gathered, I saw Unown pop up on the in-game map. Pokemon Go Fest was already a blast, I thought to myself.

That experience sums up Pokemon Go Fest nicely. The event, billed as the first birthday party for the game and developer Niantic’s inaugural real-world gathering, was held in Chicago’s Grant Park this weekend and intended to be a celebration of a massively successful first year.

As an avid player myself (I currently have almost the entire Pokedex complete and have suffered personal injury multiple times in my pursuit of catching them all), I was especially excited at the promise of playing Pokemon Go with a gigantic slice of the community. It was a chance to meet fellow players and to catch some of the rarest Pokemon in the game.

When the game was functional, it was exactly that, and there were some exciting, special moments when the crowd was working together. But for much of the day, most people couldn’t even get the game to start, leaving them standing in the hot, crowded park with not much to do but wander aimlessly. Others could connect but found the game laggy and unresponsive, or encountered crashes every time something good popped up.