Well, Eurogamer gave the original Kane & Lynch 7/10, and for my money KL2 is vastly superior in every way.
We got copies today, so I've been playing the story mode on Extreme difficulty, even after having played through the entire game two times or so throughout development then I still find it to be good fun. Extremely hard, but nothing anyone who's play COD on Veteran can't handle.
But yeah, the reviews so far are pretty fucking awful. I'm not saying that this is the end-all-be-all game, but it's definitely way better than the first game in my book, lots of these reviews make it out to be worse.