Hi there - it'll keep showing the credits because you have reached the end of the demo! Day 45 is the last day! We hope to add more days with future updates. Thank you so much for playing until the end - so glad to hear you loved the game :)
You’re right, you absolutely should be able to play Day 1-45 on other save slots too. Thank you for telling us about this - we shall investigate the issue. Sorry you’ve encountered this issue!