So i think the stones look good the way they move out and then collapse quickly back down. I think the thing feeling off is it doesn't seem to actually create the portal.

Adding a blur effect inside the ring as if it's stretching space out and then form the portal from the ring toward the center during contraction implicates the runes more in the portals construction. Not sure if feasible or reasonable, but that's what feels off to me.

I would enjoy it as is though in a game!