Fantastic!
Honestly, not a game for kids, but best in the series,hands down. Very violent, foul language, but it all works. You get some new weapons, some very intense situations, and a nice head f#$%! I recommend this game to everyone because of how much I enjoyed it.
I have not played this online, but I have heard its great. I can imagine so because the campaign was awesome. For anyone that has not run through the campaign yet, dot it! I am confident that you will love it!
Then, as it the game wasn't enough fun, they tack a zombie level onto the end. The zombie level is fun and innovative, switching away from the typical gameplay style. It was a fun addition.
Hopefully you'll enjoy it as much too!