A branch hit her across the muzzle and left
the sharp tang of blood on her trembling lips.
first thought is that if this is RD, why is she on hoof? shes the best flier anywhere and loves it besides
But
it had a little logo stamped on the back, a simple pair of wings with a bolt of lightning down the middle.
It wasn't very prominent, as if
it didn't want to get you too excited.
She had carried it like a fragile and precious thing and sat down on a couch to stare at it.
"She carried it delicately over to the couch"?
avoids stating shes staring at it twice
She picked up pace, feeling
the frustration and anger well up inside her at the memory of the letter and the weeks that followed.
i feel like the flutterdash relationship should be better established when RD sees those 2 together. it lacks impact otherwise
She thought she heard something move in the darkness behind her and turned, glaring at the shadows. She knew the forest was dangerous, but she was angry, she wasn't thinking, and she just didn't care. “Come out and face me,” she cried into the dark. The forest was listening again, there were no sounds. Then a twig snapped behind her. Rainbow Dash spun around and rushed forward, but one of her legs stayed behind. She fell over with a pained cry as the leg was twisted and pulled.
so now shes facing the same direction as she started?
The whole ground began to tremble under her as all the roots came to life,
(remove this comma) like a pit of angry snakes, and she was sitting right on top of it.(! maybe)
also, wouldnt one be in the middle of a pit of snakes?
It was a mare's voice, quite soft but wary.
i think you have to use "and"
soft and wary aren't contrary terms
She turned carefully and
winched winced
zombie RD wat!?
strong finish, but i feel like it needs more groundwork, or maybe a slightly different approach. soarin/shy is supposed to be a bombshell, but the en medias res style hurts it
edit: almost forgot: why you kill everything i love