The setup is promising. It follows a caveman by the name of Grug – voiced by Nicolas Cage – and his family, as they try and stay safe from the ravages of the prehistoric world. Grug is a fear-changing, protective father, to the particular annoyance of his teenage daughter, and while his family are safe, they never get to see the outside world. We saw father-daughter issues explored just a few months ago in Sony’s disappointing Hotel Transylvania, and the whole Ice Age franchise has been built to an extent on a father trying to adapt to his children growing up. The Croods follows the same path, pretty much treading in the footsteps of those who have gone before, as a predictable story goes through its decreasingly interesting narrative motions. Granted, that’s looking at this through adult eyes, having seen similar tales woven many times before. Younger viewers are likely to be more forgiving, and they remain the film’s key target audience. Still, it contributes to a real and notable sag in the middle of The Croods, that derails the film for quite a while. There aren’t rug pulls and there aren’t particularly new things that the film wants to say. It’s conventional in its storytelling to the very core, and it’s something that stops the film becoming something quite special. Furthermore, as striking as the visuals are, there are one or two issues. The Croods kicks off with an exquisitely animated opening hand drawn sequence, with 2D cave drawings giving the background to the Croods family, and how they’ve come to live the way they have. It doesn’t maintain that sense of identity though. When we meet the fully rendered 3D CG versions, they’re simply not as interesting. In fact, when they step particularly into the bright sunlight, they feel like computer graphics. If might sound an odd criticism, but the best animated films you lose yourself in, and only appreciate the techniques until afterwards. Here, we found ourselves thinking that it was all not quite as believable as it perhaps should be. Fortunately, Sanders and De Micco do work in some lovely touches. At one stage, Nicolas Cage appears to be channelling the peerless Captain Caveman as he falls to his apparent doom. And there’s a lovely running joke – quite a dark one for a U rated movie – about Grug’s desire to see his mother in law meet her maker. The Croods is out in UK cinemas on the 22nd March. Follow our Twitter feed for faster news and bad jokes right here. And be our Facebook chum here.