Hi melancholerik,
I have uploaded a new build (0.9.0.1) that should fix this issue that you are having. Your save file is corrupted because of this bug, so you need to go to the Options Menu and press the D key on your keyboard 5 times, this will show a Delete All Data button. Press that button and confirm that you want to delete all local data. After this you should be able to play the Story Mode.
Let me know if you have any other issues and thanks for your patience.