I have a lot to say so please bare with me.
This is a really, really cool concept. It's very original, and captivating with the world building. I love the writing and how you introduced the story. The ring of stones is interesting and can make for some really cool cinematic moments (like a long pause with skies that reflect different hues, making it look like different times of day when in this world it's a normal amount of time passing as seen at 0:14). The line "Even red... Blood red." tells us this will be a dark story. What a cool way to do it! Even showing short scenes with animals like the frog really expand the world and make it believable. With that said there are things I have to admit are lacking.
The style and animation aren't bad, the character design for this species (which to me for some reason resemble bears, they are very cute) is good as well, but because the shape language is similar in all the characters I think it makes it difficult to tell who is who, for instance at 6:43 the guy being slapped and kicked out was very confusing to me. I thought it was Roxas! To quote you from the trailer you said "This series will be a little unconventional as there is not a fixed main character. The stories are everchanging as the focus changes from one character to an other..." This is something else I feel will aid your story and writing, but with the lack of individuality of the characters designs it might bite you in the butt in the long term. I don't think the characters names were mentioned too often other than Roxas and Flare so repeating them a few times will help viewers remember them. (I think Roxy was a nickname from the other girl, to Roxas if I'm wrong that was also difficult to tell.)
Back to the animation, there are parts like the shoes walking at 1:39 and 1:48 that are repeated, which makes it look like one leg walking instead of two. Especially since they are at the same angle, careful with that. I know you have stated there aren't voices because of the lack in budget, which may be difficult at times but you can make it work. Something that bothers me is how long the text is on screen for, this might also be due to the lack of voice acting. The short lines are just right but anything longer than 5 words stays on for a long time as the lips keep going. Something that might help is voicing everything yourself, animating it, and then removing the voice afterwards. Sometimes the silence is very distracting when the characters speak. At 3:37 the music stops as if we are supposed to be hearing them, but with background music it would feel more natural.
When we get to the second story after 7:32 there are a lot of visual elements that I hope get explained more thoroughly in future episodes. Some of the violence was really fast, which might need more time to bloom and settle that feeling of death or darkness in the story. Most of the bodies were shown for merely seconds as if it's being hidden away like "yeah yeah you get the picture." which does take away from the emotion I feel you wanted to portray. If it's dark, let it be dark! The characters at the end were really interesting and the transition you did at 10:42 was really wacky and different. As cool as it was it caught me off guard and made me wonder why you decided to do that. Maybe a stylistic choice! On that note I will say the transition at 4:38 to show its a flashback was really well done, that was the only other time I could remember the transition style being similar.
I love the detailed backgrounds, the music is ominous and the story is intriguing. Something I didn't get to mention was that I love the way you drew the characters eyes, its really different. I hope you continue to grow as an artist and improve the series even more!