Unlike Modern Warfare 2, this campaign offered a little challenge on veteran. MW2 was a waltz and nothing compares to the difficulty of the veteran campaigns for World at War and Modern Warfare (don't get me started on Mile High. Only achievement I do NOT have). Still, it wasn't that hard.
I did enjoy the graphics but being from San Diego, I was partial to the opening mission. Yes, that is in fact what the inland area of San Diego looks like. All Spanish style, housing developments with houses that all look similar. Swimming underwater was interesting as well as the space missions. It lent a different feel to the game and helped break up the monotony of military bases and cruisers.
It ended with a "surprise" (not really) and left the door open for Ghosts 2.
Multiplayer is a big disappointment. There are bugs, serious bugs. The whole multiplayer experience feels lacking and ranking/unlocks have become rather complicated, further detracting from the game mode itself. Lobby hacking is in full force. You can find yourself thrown into a boosting lobby or one where someone is "out of the map" thus invincible. Then there are the spawn points. Those need to be randomized. More often than not, you will find yourself the victim of a spawn death, spawning behind/in front of an enemy or my favorite, spawning in the middle of the whole team. It's easy for teams to camp one side of a map and know where the other team will appear death after death. The dogs are a real problem. You can hit them with a grenade, a rocket and fire bullets at them only to have them survive it all and kill you.
Some of the game modes are fun. I have thoroughly enjoyed Blitz and Squad and the Extinction mode can be great with a good team of friends. Though it really is a Firefight/Zombies knock-off. Infinity Ward is definitely trying to appease fans of Treyarch's zombie mode.
A real patch is needed, not the small patch IW released earlier this week. They didn't address all the problems.