Yeah I kinda figured it out by now. Free demo goes till right after beating the goblin dude and checking the memory stone in the village cemetary.
Mountain and Forest require the passfiles that were posted a couple pages earlier. Talk to some NPC in the village to unlock. Forest ends after beating the slimegirls, mountain ends in that deserted town and the haunted mansion (I don't think there's any way to progress there beyond entering them)
You have to set the other party members as "main heroine" and unlock the ability to gain EXP and manage your party for each, otherwise they won't gain EXP and you won't be able to switch your party back around, pretty stupid honestly because most other memory stones still apply for them as long as they're in your party.
One thing I found odd though is that I could swear there used to be clothing damage in this game but it simply won't happen for me. Pretty sure I've double checked every single area for memory stones.