Since 2024, Nitrome has no longer released Flash games for browser except re-publishing Fluffball, one removed game made in 2009. Currently Nitrome are releasing games on various platforms, mainly App Store, Google Play, Nintendo Switch, Steam.
The biggest reason was security. With a huge part of the tech world running Flash, it became a massive target for hackers, forcing Adobe to release updates often to patch problems. It also offered poor performance, causing some users to see full CPU usage when viewing web pages with Flash content.