Offensive Combat developer U4ia Games has been closed down.
The US studio's creative and social director Jeremy Dunham said staff found out about the company shutting down "in the blink of an eye".
No reason was given for the closure. Around 26 employees are thought to have lost their jobs as a result.
U4iA Games was formed in 2011 by ex-Activision publishing head Dusty Welch and exec producer Chris Archer. The studio had developed multiplayer FPS Offensive Combat for browser and mobile platforms.
In 2012, U4ia raised $5.6 million in funding from undisclosed partners, taking total financing at the time to $7 million.