Thank you! I realized there's no direct message on itch.io, so I edited the original post with a link to a form so you can send us your email for registration.
Hi raverwild - the reason why we do testing on Steam is that way we can ensure people won't have a standalone copy of the build that they can pass around / easily hack, etc before the game is released.
We should have said in the post that the beta testing is Steam only, so I apologize for that.
Rest assured the final game will be released on itch.io though :)