Call of Duty 3 may seem like COD2 at times, but if you look between the bunker, COD3 is very different and fun.

Call of Duty 3 is by far best in series. COD3 takes place in 1944, when the U.S. goes into Paris. Also known as Normandy Breakout. You take place at a small camp, there you learn the basics. Soon after your training you load up into the truck. You don't go very far before you see the Germans, they are very closer than expected. One soldier begins running for your truck, and your crew tries to help him in, but before he is safely in, a bomb goes off, and sends the truck spiraling.

Call of Duty 3 is never really hard, it just has lengthy levels, and strategic situations. Graphics do in fact, look exactly like COD2. Not that it's a problem.
The most important part of the game, the "funness", is extremely succesful.
Call of Duty 3 is a very fun WWII simulation, and nothing should be taken away from that.