Extremely good graphics.
Very typical shounen (powerups, "fight for your nakama", willpower=strength, honorable fighting is supreme, etc). The "defeat boss-meet new boss-repeat" cycle of shounen manga usually annoys me, but this manga does a good effort of masking the repetitiveness.
Can't help but feel that the characters are somewhat flat despite all the character development, especially the knight guy. Too stereotypical, I guess? Characters do die though - that's a plus (too unrealistic otherwise). The main character Ryo is also good.
Author is clearly an X-Men fan. Seems heavily inspired from American superhero comics.
Being a scientific person, I found some of the scientific explanations amusing. Some were obviously far-fetched to me, to say the least, but I don't let this stuff detract from my enjoyment of it.
The story gets far better later on, tying up all the events that have already occurred so far. It even explains some of the shounen aspects, like while they've been fighting progressively harder enemies instead of getting killed early by the superbosses. I really liked volume 10, which had some very stylistic scenes. The volumes where their past is explained were also nice, since it provided a good break from all the fighting.
EDIT: more thoughts