The newly released and eagerly anticipated Hollow Knight: Silksong hit over 535,000 concurrent players on Steam within a day of its launch. 

According to SteamDB, the title hit a peak of 535,213 people playing simultaneously about 16 hours ago at the time of writing. For context, the original Hollow Knight barely managed more than 20,000 concurrent players within its first five years on the market; only with the imminent release of Silksong did the metroidvania start to see a massive increase in players, hitting 72k people playing simultaneously days before the sequel's release. 

On average, Silksong has had 359,229 people playing at a time. 

Hollow Knight: Silksong rolled out at 15:00 UK time and almost immediately the Steam store started displaying 502 bad gateway error message. TL;DR, it appears that so many people were waiting for the game to come out and were all trying to buy the title at the same time that Valve's servers simply could not cope. It appears that Steam experienced issues for over three hours. The Nintendo eShop faced similar issues. 

Silksong launched on September 4th after a long seven years in development.