All done now on variant routes, and didn't get any duplicates.
I have a question about a route though.
After solving the Malachite Portico puzzle, there is an optional thing to interact with in the next room, but it only became interactable on one of the two runs I took through that route.
Is it connected to whether or not you interact with the culvert switch early in the level, or does the optional door not get triggered if you go to the exit first?
Also I had a blind run at the Criterion version and it definitely feels like a step too far up from the basic version. I think we could have had a medium difficulty level with a few more attacks and faster-paced versions of the variant mechanics. Interestingly I seem to have seen more mechanics than some of the other players in the group, whether it's because I was running solo or I'm just a slower DPS than some. (Someone else said that the normal version only uses the blue tail, and they didn't recognise the green.)
Anyway, I might watch a guide and take another shot at it, but it's only at an "if I remember and get around to it" level of urgency.