How Many Levels Are There Really?

Hi everyone,
I’ve been wondering about this is the only level levels . The title suggests one level, but from what I’ve read, it’s actually designed with multiple twists inside that single level. Does anyone know how many unique mechanics or variations exist? I find it fascinating that a game can stretch one concept so far. If you’ve completed it, please share your experience—did the levels feel fresh, or did repetition creep in after a while?