New Q1SP: Ter Shibboleth by KenChennar alias Orl

Now, this is something else. by

An episode with five huge, experimental levels in unique settings and texture themes: a beach resort under a Golden Gate Bridge, a puzzle map set in an industrial storage facility, an Asian temple, a twisted otherworldly fortress, and a western mining town.

The levels exceed various engine limits and need to be played with the included developer version of Quakespasm.
Additional screenshots courtesy of Breezeep: