While the artwork of the series is great, it is ultimately hampered in later chapters by several things:
- Repetitive and predictable plot
I started out with high hopes for the manga: the series started out great with Death Note's likeness (the concept of the major protagonist and antagonist countering each others' moves through out the manga). However, it started growing more and more predictable - almost every new female character that was introduced wound up to be either a spy or an informant. The main protagonist is continually given the SAME near impossible tasks ("Hack the government system within five minutes") over and over again which takes away any sort of excitement towards the possibility that he might fail in his task somehow.
- Extremely bland characters
The main protagonist is probably the most fleshed out character in the entire series, which isn't really much. None of the characters are really developed. The most the author gives is the character and his or her favorite hobby that happens to help the main protagonist or antagonist. The fact that there were TOO many characters may have contributed to this. The quality may have been improved if several of the character's abilities or traits were combined into one.
- Too Many Unexpected Plot Twists with No Foreshadowing
Many of the "twists" in the manga are never really developed. You'll have a character who appears to be an ally through out several of the chapters and then suddenly turn into a bad guy. While the manga does make explanations as to why the character is actually the enemy (sometimes you can guess that the new guy is probably a spy already due to the repetitiveness of the manga), nothing in the manga really foreshadows how he or she would have done what is explained.
-Too much Deus Ex Machina
Thinking on the spot is nice, however a lot of times, the main protagonist tends to...as one user already puts it "pulls stuff out of his ass." There are a lot of times in which Fujimaru comes up with a solution that is never even hinted at all.
-Incompetent Agency
You'd think that such a top secret agency that is entrusted with safeguarding a country would at least hire some competent staff. Wrong. Many of the adult characters who work for Japan's equivalent of the CIA (in the manga) are literally being led by a kid chapter after chapter. Fujimaru ends up being an expert on not only computers, but also epidemiology and a variety of other subjects that seems to leave the adults dumbfounded. If a virus was spreading throughout a country, wouldn't it make sense for the Agency to bring in an epidemiologist? Instead, they bring one in at almost the end of manga (and it wasn't even to contain the virus).
-Flawed explanations
While I can suspend my disbelief sometimes, the author sometimes just get things wrong when it comes to explaining virology or computer science. One of them is that a vaccine can do nothing after the symptoms of the virus starts showing and that an "antiviral" is the only way to stop it on time. Vaccines CAN have an effect after symptoms show. The manifestation of symptoms is just a way of showing that a body is dealing with the virus. However, this can be overlooked by saying that the virus kills too quickly after the symptoms show for the vaccine to take effect. An antiviral merely inhibits a virus's ability to infect the body. It does not "kill it" and it would be likely that anyone who has been infected would be on antivirals for several days until their body can get rid of the virus. The correct term would be a "viricide." However, this could just be a mistake on the translator's part.