The development history of Counter-Strike: Condition Zero is pretty strange and confusing, and possibly as a result the game is kind of a mess. Sure, at it's heart it is still Counter-Strike 1.6, which is a solid, though dated, competitive FPS. Throughout its four years in development Rogue Entertainment, Valve Software, Gearbox Software, Ritual Entertainment, and Turtle Rock Studios all worked on the game. Considering that, it is not surprising that the game ended up the way it is.
Supposedly most of the time that went into creating the game was spent on AI routines for bots. This seemed to me like an odd thing to focus on. I mean, finding people to play CS with has hardly ever been an issue, considering the game's massive popularity. Granted the AI is pretty good, and depending on the settings, better than real players, though probably not better than the sort of people that still play 1.6. There was also a good deal of time spent in creating a single player campaign, but I'll have more on that later.
In addition to just being able to play the usual maps against bots, there is are a series of single player “missions” that essentially are challenges. The player chooses squad-mates, then faces off in a regular game, but just winning doesn't constitute completion, so in order to “secure” a level the player needs to complete some objective such as killing X number of enemies with Y weapon. It's a pretty poor excuse for a single player experience, but it is probably decent practice for playing competitively. Still, the best practice for competitive play is usually just playing the game.
For a while the brunt of the new content for Counter Strike: Condition Zero was a complete single player campaign. I remember reading a preview of the game and thinking about cool it would be to play an entire campaign with the cool modern day weaponry instead of the World War 2 stuff that was so rampant at the time. Now I just kind of want to vomit anytime I see another shooter with modern military weaponry. Apparently this version of the game was completely finished, released to the media for reviews, got terrible reviews, then the game was pushed back another year, handed to another developer, and was eventually released with a completely multi-player/bots focused game that I've detailed above. Much of that single player campaign was released with the game under the name Counter-Strike Condition Zero: Deleted Scenes, and after playing the first of the missions I can see why they didn't want it to be the focus of the game.
In 2003, when the campaign focused game was set to be released, it would have felt dated. The Deleted Scenes are a series of uncomplicated levels that just aren't very good. By the time it was actually released in 2004, FPS games had already evolved beyond the series of twitch shooting hallways that the game offers. In a lot of ways I think Condition Zero was released just as a way get it out there and justify all the time and money spent on it. With Half-Life 2 and Counter-Strike: Source being released months later in the same year, it is hard to understand why anyone would even bother with the game instead of just waiting because these games blew the single player and multi-player components, respectively, of Condition Zero out of the water.