It's not an RPG - there are no battles, and the story is totally linear.
Yonaka Kurai, an extremely ordinary high schooler. She takes the usual train home.
Though it's all ordinary, today is somewhat special. Today, her beloved brother comes home.
But when she wakes, the train has stopped at an unfamiliar station...
Mogeko rates this game "ages 15 and up."
(This rating is Japan-centric and would likely be more strict by other countries' standards; 18 and up may be more appropriate.)
It is very violent and contains instances of implied sexual assault, with the bad endings being some of the most severe parts.
I would advise against playing if you think you may be upset by such content.
Download Mogeko Castle 1.12 | (Mirror)
(Please disregard if Chrome tells you the file is malicious; this is in error and beyond my control.)
Installation of the RPG Maker VX Ace RTP is required to play.
Mac Version Available from RPGOSX
Some have experienced crashes during the final chase scene.
I'm unsure of the cause, but I would expect it to be related to the large number of events in that map.
If it consistently crashes, download this save, copy it into the SAVE DATA folder, and load slot 20 to skip to after the chase.
Though the game is quite straightforward, there are two parts in particular which require some trial and error.
So I figured I'd be nice and give the answers here, if you want to "spoil" yourself.
Middle, left, right, middle, middle.
Chase to Floor Seven
Keep going up at the first split, then up at the second, then right at the third.
Keep going until the next split and go right, then open the door at the end of the passage.
Go down at the split, and keep going to the door at the end.
Go down at the split, then quickly go through the door in the open area. Lastly, just keep going up.
Also, there are some things you might miss. (Spoiler warning!)
Bad End 0|
At the front door of the castle, choose to look for another way.
Bad End 1
Check the crazed Mogeko along the dark path on Floor 1.
Bad End 2
Enter the top-right door on the Bowel Path on Floor 2.
Bad End 3
Push the button to open the big cage on Floor 3.
Bad End 4
After Hasu's ascension on Floor 4, backtrack from Moge-ko's room.
Bad End 5
Touch the Blancfluff Mogeparasite in one of the rooms on Floor 5.
Bad End? 6
Outside the library, elope with Defect Mogeko.
Bad End 7
Get caught by Shinya.
Kill at least one of the special Mogekos.
The Door of Truth will present you with the Path of Paradise.
Either don't kill any of the special Mogekos, or continue after the normal end,
and choose the Path of Falsehood.