Ok, #terminalphase can load multiple levels in a row now. Doesn't sound like an amazing feat (and it kind of isn't) but took me a bit to think of how to do it nicely given the structure I had. Happy with it enough. Now to replace Level 2 with something actually fun to play.
I'm not very happy with the ending of #terminalphase levels either... I'd like to have some kind of boss fight per level, which is what many space shooters do, but I'm on limited time until the release.