Howdy!
The way it unlocks changed after that comment 3 years ago. After speaking with different townsfolk, they'll tell you about their strange experiences in the town. After you've had a few of these happen, the next time you sleep you'll have a particularly strange dream, and the vending machine unlocks the next morning.
Thanks for checking out my weird little game after all this time, and for your support! It's neat to know that people are still experiencing it all for the first time! ^^