I personally liked it okay. Of course, comparing it to Deus Ex makes it look like an attempt to throw together a sequel while pandering to the "cool kids" of the early 2000's. I mean, the tag line is literally "the new war on terror" with a dude on the front holding a pistol sideways with the douchiest hairstyle I've seen in a while. Due to this, I played a female character ('cause that's an option for a 2003 game; color me impressed).
Look at it this way. The first Deus Ex was a blockbuster movie that set the bar for years to come. Invisible War was the mediocre animated series on Kid's WB that only existed because it can point to the original and say, "See! We're that cool!" Some people will hate it, but some people will... well, not LOVE, but still find reason to like it. And yes, you can actually directly troll the Illuminati in this one. Hell, you have a chance to troll everyone if I remember right.
One final word. To further what someone said earlier, it was quite obviously made for the Xbox early in its run. The UI is pretty crap, and the omni-ammo will get you killed in a hurry if you try and use a sniper rifle or rocket launcher for very long.
But hey, you have it already, so give it a shot.