It reminded me of House of Leaves, but then again, so does everything. In this case especially because of the setting and the unreliable narrator, as well as the "experimental/exploration" vibes of it, albeit House of Leaves really gets into it right away, while Piranesi takes a little while to make you realize "huh, something's weird here." In that way it reminds me of a classic (specifically Journey to the Center of the Earth by Jules Verne), since it doesn't really bother to get your attention at the start and only gets good if you stick with it. I admit, if you let yourself get wrapped up in the details, instead of just being swept along by the story and getting immersed, it can be a bit of a drag and tiring to read. There's kind of a slow build up of tension, and then all the sudden so many things are happening and there's almost a plot. Also, the ending was pretty quiet, but so was most of the book so I think it worked. Overall, I think this is an interesting little book that I'd like to reread sometime, as there's probably plenty of foreshadowing.