I think I finished it!
A downloadable game for Windows
Nightmare Castle is an extended technical demonstration and a surreal adventure game from 2013-2014, built as a platform to test reduction and refinement of RPG Maker's VFX to PC-88 or early PC-98 standards. As such, the game uses 3-bit graphics at a resolution of 640x400.
Unlike Amihailu in Dreamland, the gameplay is a direct descendant of Yume Nikki.
Simply unzip the file and run "game.exe" to play the game. The RTP for RPG Maker VX Ace is not required.