You do not say what version of Harem Hotel you are playing.
In version 0.17.x there is a bug that sometimes prevents Maria from getting past level 30. That bug is fixed in 0.18.x version.
Then it should work. I did not see this problem.
Altering nia_alert00 should not be needed in version 0.18.x, maybe manipulating its value breaks things?
I don't know, but I didn't change the data until I finished all the characters
I can not help more.
Perhaps the old bug was not completely fixed if it can still appear.
Can you provide debugging info, or stuff that might help the developer examine the situation?
You could tell for example is this a fresh install of 0.18.s, or 0.17 upgraded to 0.18.
I haven't updated the game, so it's 100% a direct install and not an update from 1.7 to 1.8
If there is no way, I will try the next version.
