What was the FIRST Valve game to have VR?

The first Valve game to have VR was The Lab. This game was specifically designed to showcase the capabilities of virtual reality and demonstrate various VR experiences. It included a collection of mini-games and experiences that were optimized for VR technology, allowing players to interact in immersive environments. The Lab's release marked Valve's initial foray into the VR gaming space and served as a significant milestone in the company's exploration of virtual reality.