That's strange! I'll look into it. Sorry about that!
No worries, thanks! Btw, in case any more info is helpful, I'm playing on Linux and basically just dumped the game files all in one place and am running the Terra_Nill.x86_64 executable directly in the terminal. Also, I think after playing a bit longer, the game is correct saving that I have completed level 1 even after I re-load the game, and while I'm playing the game, I can return to menu and then hit 'continue' to pick up where I left off. However, if I re-load the game before completing a level, that's where I seem to not be able to hit 'continue.' Best wishes with your game.