docfate: In the current build you are unable to rebind keys via the game, but if you hold down the "CTRL" key when you double click on the launcher you get a configuration screen where you can redefine them.

However, the changes don't seem to stay rebound between sessions so you have to keep doing this every time you launch. (Edit for clarity: the changes stay rebound in the configuration screen; you just have to launch via holding down CTRL every time you want to play in order to use your rebound keys.)

The developer has said (on the Steam forums) on that they will add rebinding controls to the game in a future release.

I'm left handed. WASD doesn't cut it for me so this is a very important feature.