So I got this game through the humble bundle, and I want to know if I can update this game at all.

And if I can, how would I get my purchase of Voxatron through here? How would I get the updates?

You can download the latest update by heading to the download page attached to your Humble Bundle e-mail! Zep is planning to create a different updating system, one that would use this website, but for now we have to stick with the little hassle. Cheers!