Thanks! Looks like logged out the collection isn't accessible at kbin.social/c/collection-name anymore which is excellent, but is still accessible there when logged in (unexpected, though perhaps only accessible to my account, but I feel bad I might be squatting on a nice collection name) and is also accessible at kbin.social/u/gibandaley/c/collection-name (expected)
Yeah, I favorited my private collection (not sure why I did that...) and it seems to have permanently made it public, no big deal in this case, but I feel bad 'squatting' on collection slug.
I finished Psychonauts for the first time a couple of months ago, and just started Psychonauts 2 last night. Only a couple of hours in, but really enjoying it so far.