Thanks!
I had the very loose concept of trying coop game mechanics, hence the need to share an environment but let each player explore it separately. Or was it just an excuse to try my hand at dynamic split-screen? :'-) Unfortunately I quickly lost motivation and barely touched it after mid-june.
I'm honestly not sure if I'll try to make a real game from it, but I've already had an interesting discussion on discord which pointed at promising improvements in the way the effect is done.