Quick description of the bug here:
First issue is that on the main menu, it asks me to create my online account. Once I've done this, I can get into the main base area (which will usually throw an Unexpected Error).
Upon trying to launch ANY mission, it throws a "Server refused the connection" error and kicks me back to the main base.
I was intending on doing an extensive bug report later on but I can't really do that now since I can't actually play to FIND the bugs :P
Still, from what I've played so far it's a pretty solid alpha. Keep up the good work!
EDIT: Nevermind, should've read the known issues post!
EDIT 2: Workaround did not work.