I'll start my review by telling you the major weaknesses you have here. Pacing. The plot moves way too fast. You don't give us a reason to like Ryu's parents or a reason to care for those guys who got blown up. They just died. Everything moved way too quickly and in just about 1000 words, Ryu already has motivation for revenge. Some details here and there would be pretty neat.

Next, show, don't tell. From the first paragraph alone, we get to know that Ryu loves Vanguards. A better way to showcase this instead of just telling the reader is to have Ryu gush over a Vanguard he saw up close or one he saw in a magazine. That would give us a clear picture of the kind of person he is.

Thirdly, plot holes. Masked man, why didn't you just check his pockets on the spot?! He was tied up, for goodness sake! And wait, how'd he pilot the Gungnir if he was tied up? Did the rebels actually untie him? Really?

Overall, it's a neat story but it can use some improvements. Slow down the pacing a little and make us care for the characters. Ryu wasn't able to captivate me as a protagonist just yet. We didn't even get to know who his friends are either. We can't relate to him because we don't see any, if not much, interaction between him and his friends and family. So let's just say... We don't care that they got killed.

Alice is an interesting character to me. I'm guessing she's a robot or something.