I unlocked the arcade and clicked on it on the main screen. This takes me to a screen with an arcade machine on the right side and an empty "Steam Leaderboard" on the left. After clicking on the arcade machine in any way I can think of, nothing happens. How do I play the arcade?

Note: I installed the game via Backup Installer and not Galaxy. Could that be the issue; that it somehow requires Galaxy to work?

To start the arcade mode, you need to click on the arcade machine after going there from the main menu. I have confirmed that this only works when you are both online and using Galaxy. You can easily see that it's not working if the leaderboard is empty. Clicking on the arcade does nothing then. I have contacted the developers about this, but they haven't gotten back to me yet.