A sufficiently absurd live-action adaptation of a long-running manga / anime series, in which a giant, yellow, tentacled, smiley-visaged alien spends a term as visiting professor at a Japanese middle school. Having already annihilated a majority of the moon, he's promised to do the same to Earth if he survives the class, though a core subject is his various weaknesses and how to exploit them. So basically, pop culture in Japan at its usual level of overly-specific weirdness. It's actually a great recipe for fresh stories - downtrodden kids from a discarded class learning the ins and outs of the assassination game at a very young age - but often gets tripped up by its own rules and a desire to be more than just a silly dash of action nonsense. The CG can be interesting, too, but there's so much exposition that, as a non-native speaker, I was always too focused on the subtitles to properly appreciate it. Several desperate attempts to make an emotional connection near the end seem misguided and ineffective, merely distracting from the main attraction. Too much fake heart and not enough real heat.