Hi Valdeir,
Thanks for this!
We will be implementing rebindable keys and other options at some point in the future.
Unfortunately we won't be able to offer character customization as we are a small team and the workload to make it really satisfying prohibits us from implementing it. Hopefully you'll grow to like either of the two characters you can play as though!
We'll have a look at the rest of your feedback when we get a chance.