As avatars we each have a backstory.
As typists we each have a backstory.
And as characters in film, we each have a backstory.
Long ago in my infamous movie group days backstories were a hot topic. What motivates your character? What is their history? Childhood, bosses, family, lovers and friends all play a part in the drama behind the drama of your characters.
In machinima we often don't have time to let that unspoken history shine through -- a few minutes isn't really enough to peel the layers of our protagonists. That doesn't mean we should forget that part of the process.
Let's take an example. Your lead character's partner dies. Typically they would be in a sad state, but what other layers are beyond that emotion? Does it remind them that their father died early in her life, leaving them unexpectedly just like their partner? Is some part of them relieved as they know the beatings will stop? Are they worried about supporting the children? Each idea behind the character alters the emotion.
Some of use make stories where our characters interact; some make narratives where the poem or prose invites the viewer into our world. Some let the pictures and the layers within the pictures tell it all.
Whatever your method, try thinking a bit more about the emotions of your characters. I am betting a new layer will be inserted in your film.