[quote name='mortalgroove']Would this game be ANY fun for single player?[/QUOTE]
I've been playing it solo and it works very well. The AI needs a bit of nursing now and again but it's more than capable of working with you. It functions as a very nice third person shooter by itself. I will tell you that the AI has saved me twice as much as I've saved him, and regularly gets about 75% as many kills as me, so it's respectable.
Pretty big fan of this one, but more than $30 might be a bit much. The online MP is tepid. Lag is annoying. The gunfire has noise and flash, but no oomph. Your guns don't feel as violent and powerful as they should in a game like this.
The cheese that made the original so good is served up pretty well here, with more fist-bump and anti-fist-bump actions and even the ability to play rock paper scissors with your partner complete with hilariously over the top gloating animations for the winner.
Shanghai is woefully underused, but the setting is crazily colorful. The game isn't technically beautiful but there are a lot of nice eye-candy bits.
Weapon modification is there for even more cheese. Pimping your gun doesn't look nearly as cool but there's tons of options in the game's awful menu to try to eke out miniscule stat-ups from your guns. Not really worth it because of the awful menu, but the variety is nice.
Speaking of the awful menu, there are many ways that the game doesn't feel polished (Unskippable cutscenes. Silly menus. No way for both players to shop at the same time.). The upcoming DLC that is clearly cut levels from the SP to make release is such an example. Still, it isn't a bugfest. It delivers the gameplay pretty dang well.
All in all, a solid third person shooter that is good by itself but great with a friend. Get it cheap and enjoy it. Skip the MP.