'Blue Heaven' is a manga that aspires to be a lot, but doesn't quite reach its potential. While it has solid artwork and an engaging plot with well-rounded characters, it's clear that much more could have been done.

[Story - 7]

The premise itself (a killer is brought onto a cruise ship and is unleashed) is rather intriguing (especially for a manga this short), but it doesn't quite reach the heights of tension it could have. This is due to the plot suddenly changing into, for lack of less spoilery descriptions, Neo-Nazis Reveal Themselves And Take Over. I don't mind plot twists like this (especially ones where such awful people get their comeuppance), but the original premise itself was enough to get my interest. I really don't see the point in such a change, and I found it rather lazy.

I can tell that the mangaka was going for themes such as 'are humans irredeemable?' and 'what will people do to each other when in a crisis?', but it doesn't feel like he achieved what he was going for. I don't quite know how to describe this, but it just felt like there was a lot more to be explored in this story, setting, and characterization than what was done.

The pacing was pretty good, though - thanks to the short chapter count, it made for a nice weekend read.

[Art - 8]

The art's really hit-or-miss in terms of aspects. Character design is distinctive but simple (such as different types of facial hair and hairstyles), while the backgrounds are either rather well-drawn or too minimalistic. The shading was REALLY good - perfect balance between moodiness and....the opposite of that.

[Character - 7]

The characters, like the story and themes, are intriguing enough but their full potential wasn't realized:

Ri Seiryuu is an interesting deuteragonist with a fitting, if edgy, backstory and a rather stoic characterization compared to everyone else; However, I felt that his 'arc' needed a more solid conclusion. I contribute this to the sudden plot twist, but it just felt really weird to have him still be in the story and it's clear that he doesn't match up well here when he was the initial antagonist.

Yoshiko is probably my personal favorite - she's really cute and provides some humour, but the way she was written as the mere 'observer' of the events on the ship was rather competent. The mangaka really captured the sense of desperation and despair someone like her would feel, and it was conveyed so believably.

Other characters, however, aren't so memorable or well fleshed out compared to those two. Security agent Sano is barely memorable due to his sudden removal and return (thanks again to the plot twist), Jyungo is a typical Nice Guy that Yoshiko likes, and.....I can't even remember the second half's antagonist besides him being a larger-than-life Genocide Lover who felt more like a parody than a believable antagonist.

[Enjoyment/Overall - 7]

This wasn't a terrible experience, and I did enjoy myself thanks to the tension and strong characterization of Seiryuu and Yoshiko. However, it's frustrating to see how much potential this manga had that wasn't appropiately realized. I would recommend this to anyone who wants a good thriller, but not if you want a thriller with lots of psychological/philosophical depth.