>>219567I've watched all the things and I honestly still don't understand half of it. So just watch them in release order, I guess. I think I skipped the 5-minute PV though since I couldn't find it.
Just know that they're all basically the same story and same animation. Each one just adds something different to it that wasn't detailed in the previous ones.
As such, I think the most recent anime, the 13-episode one, is fine to view as-is without any of the previous ones and is also the best of them all, in my opinion.
So go for release order or just the 2013 TV anime. If you end up liking the TV anime, go back and watch the others. They mostly just give a clearer picture as to what's happening. If you want a more surreal experience, maybe just watch the 25-minute ONA, since it gives the least information out of them all.
Sorry for being really wishy-washy. Hopefully this was helpful in some way.
