aaaa I'm sorry to hear that! T_T What exactly happens once you reach Day 2? If it's possible, can you copy the text or give screenshots?
What was the last scene you got before it sent you to the title screen? And have you tried picking all the different options? What version number is displayed in the top right corner of the game?
There are certain choices in Day 1 that can automatically lead to a Dead End (instead of continuing the demo), which will cause Ren to "confront you" and send you back to the main menu.
But if the version number is below 3.0, you'll need to download the newest version.