What happened to the creator of Gunman Chronicles, Valve's forgotten FPS? 'My relationship with Gabe didn't really go that great'

Gunman Chronicles launched on November 21, 2000, and received mixed reviews from critics, which is still a sore point with Flower. "When you see reviews and they're like, 'Oh, this game is too much like Half-Life!' And you're like, 'What, the best game that you ever rated? Too much like that, huh?'" The game sold relatively well, although Flower says he "didn't get rich" off his cut. "I probably could have made as much money painting cars, as far as take-home money. But royalties are taxed at a lower rate, so it spent pretty good."

On one hand, it's already huge success that your game is being compared to HL1, on the other hand, that's one tough competitor.

How have I never heard of this game until now?