Oh yeah, I knew it! Looming makes me think of both Myst and Yume Nikki, and it turns out that's what it was based on! Yay, I'm happy, for some reason.
This is an excellent game, I love this kind of atmospheric adventure where you have to explore and find artifacts, discover the history of the place as you go along, and unlock new places whenever you finish doing something important. The atmospheric feel of the monochrome graphics coupled with the eerie sounds makes this one of the most involving browser game experiences I have lived to date.
I only wish there was, like, an extra room for every portal, just to add more eye candy, but this was still pretty great. The only thing that truly pissed me off a bit was the second portal. I'm not sure if I should be spoiling this or not, but how on Earth was I supposed to know to wait a minute before entering the exact same portal I already entered before?
Still, other than that, this game is amazing, and it shows that Gregory probably likes the same kinds of games I do.