It's a rip off, a poor man's version of CoD: MW running in an old graphics engine, but it's an awesome budget shooter...
The game is SP only it has a 8 - 10 hour length (Much more than today's average full priced shooters), it runs on the Jupiter EX engine (F.E.A.R.'s engine), it may look dated, but unlike other shooters form the same developer, they took the time to make new character models, scenarios, missions and enemies.
The locations are varies, from an airplane mission that resembles a lot to the bonus mission of Modern Warfare 1, to offices, airports, basements, etc.
You won't be fighting the same bad guy over and over it has many models of enemies, and different kinds of weapons, such as assault rifles, light machine guns, shotgun, hand gun, Sub machine guns, and a very versatile FAMAS rifle which can be reconfigured to become a silenced sniper rifle.
Every weapon has been greatly modeled, most of the weapons are recycled models form other shooters of the same developer as CoH 2, SAS: Secure Tomorrow, etc, but the weapons look, sound and work very well, you'll feel like you're shooting a real one.
Firefights are very intense, sometimes frustrating, but with lots of enemies with great AI inherited from F.E.A.R. long levels, very detailed, the old graphics engine may not be as fancy as most games, but it manages to look good enough and runs pretty smooth.
The bad news is that the game is very frustrating, there's a level in abunker specially frustrating, but very intense too.
The main problem is that CoH 3 served as the base for other budget priced shooters from City Interactive like Terrorist Take down 3 and Armed Forces Corp, they all share the graphics, enemies and weapons, but they are actually awful games.
If you're tired of CoD and its 4 hour campaign give CoH 3 a chance it's the best and most intense budget priced game and perhaps the best budget game ever created with a more updated graphics engine it could have been a great modern warfare shooter.