Not Well-known Anime - Tumblr Posts

I’ve been trying to remember this anime I watched. I only saw the opening and never got the chance to see the whole thing but I want to now. It’s not super famous.

Here’s all I remember from the opening:

1. The song was really upbeat.

2. In the end, a dark-haired(maybe purple) girl sees a pink-haired girl sitting in those tubes you see in the playground. Then they starting running through a field together without shoes. They may be holding their them.

3. The setting kind of goes gloomy and sad near the middle of the opening. I believe there was a boy and girl with instruments- a piano and violin respectively.

4. There was a large group of people with white hoods.

5. Near the end of the opening there was a small person- maybe there were kid- standing back-to-back with a extremely big person.

6. I kind of remember a guy maniacally laughing

Thanks to anyone who knows and comments. 😁💕