Sonic the Hedgehog's teeth and why video game movies struggle.

On the face of it, it's such an obvious idea: take a well-loved video game and bring it to the big screen. After all, a successful game and a successful movie have so many ingredients in common. Engaging lead characters, a scary villain, a nice easy-to-follow plot about, say, rescuing a princess... Now of course that's Twitter, where the first response...