OTP is currently down for registering users please sign in through steam via the steam button at the login screen.
Will post update when this is polished and fixed, thank you!
Registering account OTP is down. Use STEAM login to play.
Source: Steam Community (opens in a new tab)
Build and release context
Recorded Steam release date:
Within one calendar day of this post (UTC). The listed date does not establish an exact launch time.