First off, I have to commend you for your summary. Gripping words there.
Second, your execution doesn't live up to what is expected from the summary. While there's nothing wrong with the story's construction thus far, there are many things that could be added. All the reader can infer is that some sort of explosion or some military backed event killed Sonic's friend and brother, but the reader is left in the dark as to what exactly happened. What kind of explosion? Were there other innocent civilians involved? Is there currently a crowd at the scene? Smells? Sounds? Details, details! A rundown of the five senses would be nice.
Also, the comedy is not working for me. Sonic's distress is very gripping, but the shots of Amy kicking Shadow just ruin the mood. It is hard to find Shadow's quips funny when there's trauma going on with Sonic.
It is still the first chapter, so I'll keep reading and I will hopefully see what you can really do once the introduction is over and done.