While overall I enjoyed your story extract I think there where some minor flaws that if it was any longer would of completely ruined the whole story for ME.
Shadow : Do you wanna go to da p r o m with me?
Extract like this show that while the storyline is interesting (it included my two favorited characters of all time (I wish they where real thought)) shadow doesn't speak like the real shadow. Shadow is well know for his 'cool' and as some haters say 'edgy' personality and this fan-fiction shows non of that. I would go as far as to question your real legitimacy as a fan of shadow and fluttershy. If you was a real fan you would know the first and last voice actors to voice shadow there date of birth and address.
[1]Shadow : I knew you would say yes. I am shadow afterall. Much better than Sonic.
Furthermore the sonic - shadow rivalry was really not show as much as I think you should have displayed it. (As seen it quote labelled [1]) Instead it should say something like (bear in mind I am not a proper writer like you but I am a FAN)
Shadow:I AM SHADOW LORD OF THE UNDERWORLD AND STRONG AND FASTER AND BETTER THAN SONIC!!!I will critique the rest of the 'fan' - fiction later. Thank you.
EDIT: You spelt SANIC wrong :(
Edited 5/2/2016 20:06:10