rating: 2.5The law of diminishing returns finally catches up with the highly popular Ice Age franchise, for Continental Drift, the fourth entry in a 10-year period, is the first that doesnt purport to offer more than its predecessor on even a superficial level. Things open once again with the amusingly mischievous squirrel Scrat who, still in pursuit of his beloved acorn, ends up tampering with the Earths core and causing the titular world event. This shift causes woolly mammoth Manny (Ray Romano), sloth Sid (John Leguizamo) and sabre-toothed cat Diego (Denis Leary) to be separated from their old crew, chiefly Mannys mate Ellie (Queen Latifah) and their rebellious teenage daughter Peaches (Keke Palmer). Meeting a fleet of colourful new characters and contending with some fearsome foes along the way, getting home wont be easy. What leaves a sour taste for most of this sequel is its eagerness to simply follow the formula of its forebears, wherein an event inconveniences or splits up the gang and they then have to, against adversity, make it home, segmented by small sequences featuring he who has always been the series' biggest draw, Scrat. The visual wit of these small portions remains strong particularly one in which Scrat discovers a bountiful, Greek acorn utopia yet only compounds the disappointment that most everything else is so unimaginative and moreover, unfunny. Though the filmmakers have tried to introduce myriad extras to liven things up including Sid's dappy family, a rowdy rabble of chipmunks, a gang of angry sea pirates, and some dangerous Sirens this sling-as-much-as-possible approach is ineffective because it runs the charm gamut so low. It is only Jennifer Lopezs femme fatale Shira, a sassy, sabre-toothed love interest for Diego, who really makes much of an impact, though thats down more to J-Los strong voice work than anything the script has to offer. Of course, the familial concerns that have characterised the series are still here, and with Peaches now growing up, there is certainly plenty of room to move this forward. However, she and mama mammoth are kept off screen for such long periods while Manny, Sid and Diego travel the seas that theres little-to-no chance for character development. This is something that admittedly has never been the series strong suit, and typically what keeps it at arms length of amassing Pixar-level plaudits. The pervasive problem throughout is that there just isnt much effort taken to the move the characters on, and given the depressing lack of laughs, this gives it the overwhelming feel of an cynical and arbitrary sequel which, given the near-$900m smash success of the last film, it absolutely is. Its a particular shame as recruiting the likes of Peter Dinklage, Wanda Sykes and Patrick Stewart certainly seemed enticing, if only their talents and voices had been matched to something wittier, more heartfelt, and therefore, more entertaining. With its focus on the circle of life and the eventual void of redundancy that parents fear they might fall into, Ice Age: Continental Drift could have served as a sweet way to bring the series to an emotionally well-rounded close. As it follows, Sids buffoonery will probably still entertain the very youngest children, but the wit and charm of the series earlier entries, and much of their visual splendour, appears to have evaporated. The where-do-we-go-now cliffhanger blatantly baits a fifth film, but if that is to happen which, pending box office receipts, it surely is the filmmakers will need to go back to the drawing board. Ice Age: Continental Drift is in cinemas July 13th.