I'll save you the Google search: Chronotopophobia isn't a recognised fear, but a word invented by the developer that suggests fear over time and place—a fear that manifests here in the frightful subterranean world your character finds themselves in after binging too much on Twitter.
If you've played a Bitsy game before, you'll have an idea of what to expect: a mechanically streamlined, low-res browser game focused on exploration, and dialogue or narration, with environments or sprites that might be difficult to decipher. As an example of the form, Chronotopophobia is extremely impressive: the backgrounds are monochrome, but detailed and easily readable, while there's a rich, engrossing soundscape that fills in many of the visual gaps.
This is a hugely atmospheric horror game. I'd place its psychic landscape and cosmic existentialism somewhere between Lynch and Lovecraft. Figures spout poetic, semi-coherent monologues as you explore the cavernous underworld. At some point you'll either run into a dead end, like I did, or figure out what the hell you're supposed to do next. Either way, you'll have enjoyed, most likely, your descent into its horrific realm.
If you're ready, you can dive into Chronotopophobia here.
For more great free experiences, check out our roundup of the best free PC games.