This messy, jumbled game development is what lead to the game essentially being split in two. Counter-Strike: Source's release later that year all but buried this game, which was never popular to begin with. By that time video games had progressed a fair bit, and the graphics of CS:CZ were very outdated.
Development began in 2000, the game was announced in 2001, but due to Valve constantly handing it off to different developers (including Gearbox led by Randy Pitchford), it wasn't released until 2004. The game itself actually has a pretty strange history, and I'm surprised it was ever even released. I think it was the result of part of me wanting to play some Counter-Strike, but the other part of me wanting to play a single player game.
I don't know what on earth possessed me to play this game.