As was stated in the devlog we'll be releasing steam keys once we've gone live on Steam. We're going live on Steam tonight at Midnight PST. We hope to have the keys available by this weekend.
More specifically:
Tomorrow I'll be getting the keys from Steam and sharing them to purchasers on here. The process is done through Itch.io where you can claim a key. I'll send out a bulk e-mail to all people who have purchased the game (as long as your e-mail was included in your purchasing receipt) which will include instructions on how to get that key through the itch website.
Because this is our first Steam release, and I've never set this steam key handout through itch before, there may be a learning curve I'm unaware of. So please be patient as we try to get them out over the next couple days. I want to have it all set up by this weekend.