Hello and thank you for giving the game a go. Part of a failsafe due to path crossing issues, ones you start Seiko or Heather's story, the other girl's door will be locked. So you must finish Seiko's story before Heather's door unlocks. There free roaming will be much back in part 2. It's just me who messed up and had to do an extreme path blocking fix because of it. Cheers :)