I took the kids to go see it yesterday and I thought it was brilliant. Whoever does the writing for these guys really know how to keep the adults amused with subtle references while giving kids the slapstick and more overt humour.
I don't think Shrek 2 is QUITE as good as the first, but it's still damn good. If they keep it up, they could easily squeeze a Shrek 3 out of the franchise.
