I've been doing some early character designs today, playing around with a few different expressions. I'm still not 100% with these but think that this is the direction that I want to take in terms of the look of the film as it shows clear and effective expression. 

As you can see the far left design is pretty bad, the proportions and structure are way off, which creates a really unappealing design. The other two in the picture are much more appealing as they demonstrate better facial structure which creates a much clearer expression.

This is a little expression test that I did to see if the two drawings aligned. I think it works quite well in showing a transition from happy to angry but will obviously need to be fleshed out with inbetweens.