The first thing you'll notice is the very old looking character designs, this is because it is based on the unpublished script by Leiji Matsumoto from the 1980's. Some might be put off by them, especially if you have only watched anime post 2000, but I think it provides a good example of how anime has changed visually over the years, and would hope that people would not avoid the series because of the old art. The animation was of a good quality throughout the run, and the CGI which was used often was mostly done well, although there were one or two instances where it looked slightly awkward.
The soundtrack for Ozuma did it's job satisfactorily though it didn't stand out very much due to it being forgettable. The ED, "Utagoe" by Minami Kizuki is a pleasant track with some soft piano, however it is the OP "Neverland" by F.T. Island that will attract your attention. There is both a Japanese and an English version of the opening, the version you will hear will depend on the source of the episodes you watch. Both versions are decent tracks, though I much preferred the English opening.
The setting was initially very interesting, the earth has turned to desert due to increased radiation, and the cloned people called the "ideal children" rule over society. I thought this all had a lot of intrigue, and hoped that we would get interesting revelations as the show progressed.
Unfortunately nothing much came of the setting, and this is where it starts to go downhill, most of Ozuma's problems (including this one) stem from the aforementioned length. This is only 6 episodes long, but there was enough content to constitute over twice that. As an unavoidable consequence, this was very rushed. There isn't much time to build up to revelations, develop characters, or even have a satisfactory plot.
The plot seems very simple at first, with Sam (our protagonist) saving Maya from her pursuers, followed by a battle that mimics submarine warfare. In reality the plot should have been much more complicated, with politics and important biological themes, namely "species which do not evolve will not survive", however, despite the potential for a complex and interesting story, it is mostly glossed over due to the time constraints, which is a massive shame. The mystery about Ozuma (the sand whale) was interesting, but the way in which we found out it's true "identity" was underwhelming, and a plot twist concerning Gido was fairly obvious.
Due to the fact the characters were conceived in the 1980's, they have the common personality quirks from that time, and are likable, though most of them are only in the background, since there isn't any time to cover them. The main characters suffered from a lack of characterization, and with the pace of the show, there was no time for proper character development or any change in the relationships between the characters. The way Sam and Maya interact with each other stays the same throughout, which was disappointing. The only main character that stood out was Bainas, as she was an intelligent commander who was entertaining to watch, and progressed the most as a character, which was still too little.
Ozuma is enjoyable most of the way through, the battles that take place beneath the surface of the sand are well executed and make use of clever tactics, and because they are like submarine battles, you can actually understand what's going on to the full extent. However by the end, where the pacing of the show is the most rushed, I found everything so underwhelming that I wasn't so much unable to enjoy it, but I just stopped caring about what was happening.
To conclude, there was far too much content for the time available, which resulted in an anime which was disappointing, and left you with a feeling of indifference, which is a pity considering how much potential it had and how likable it was at the beginning.
