Shrek The Third was such a steaming ogre turd that anything better than it was a welcome relief. But whilst Shrek Forever After is indeed better than its precursor (not hard, as most films are), it never achieves anywhere near the success of Shrek or even Shrek 2.
Granted, Shrek Forever After does have some good ideas contained within it. New antagonist Rumpelstiltskin (Walt Dohrn) is effective enough, despite being an amalgamation of features from the previous three baddies seen in the Shrek franchise (Lord Farquaad's diminutive stature, Fairy Godmother's magical contracts, and desire to be king from both Prince Charming and Farquaad). Another entertaining new adversary is the Pied Piper, although his appearances in the film are disappointingly brief. The alternate universe story is set up well and provides a handful of imaginative concepts, although as the story wears on the ideas start getting less and less fresh. Shrek's (Mike Myers) get-out clause in his contract with Rumpelstiltskin, for example, is lifted almost entirely from Shrek 2.
Despite these redeeming features, there's also too much within Shrek Forever After that simply doesn't work. The tribe of ogres, despite being voiced by current talents such as Jon Hamm and Jane Lynch, feel like a collection of flat Shrek clones (apart from Craig Robinson's excruciatingly unfunny chimichanga-peddling Cookie). Shrek's rebuilding of his relationships with his old friends in the alternate universe also provides one misfire after another: Donkey (Eddie Murphy) feels underutilised for the second Shrek film running; Puss In Boots (Antonio Banderas) is turned into a one-note lowest-common-denominator visual joke (he's fat); and there's never any spark in Shrek's renewed courtship of Fiona (Cameron Diaz), who is presented as a nearly-twenty-years-too-late Braveheart parody.
In the end, Shrek Forever After is undoubtedly much more worthwhile than Shrek The Third, but still provides a weak and largely unsuccessful conclusion to the Shrek series. It's a shame to see a franchise which built its foundations on witty subversion of stereotypes and conventions in its first film largely fall back on trite and unimaginative ideas as it draws to a close. Sadly, Dreamworks have made sure there's absolutely nothing left to wring out of their flagship ogre before allowing him to retire to his swamp for the final time.