The story is pretty standard when it comes to adventure films, and it seems to have taken much inspiration from classic black & white jungle adventure films of the 30s and 40s such as King Kong, Gunga Din, or the many others that were released during that era. However, the plot here doesn't have much of a structure to it, jumping from one scene to the next without much of any reason or purpose other than to showcase some action or animation. Much of the middle of the film is spent in action scenes that exist for little to no reason, where many of the characters' goals and motivations aren't resolved or moved forward in any way. This tends to make things drag quite a bit. There's also a plothole here and there that will introduce questions that never get resolved, and were seemingly overlooked by the directors. I will say, however, that that main story at both the beginning and the end of the film are well executed, but still aren't anything other than average in terms of content.
The characters tend to be somewhat enjoyable, but also aren't anything special, and the biggest problem I have is with the lead character, Wataru, who tends to change his tone and behavior from scene to scene. In the beginning he starts off as timid and shy, then once he's separated from his father he runs for his life. After a day or two has passed, he suddenly becomes able to do acrobatics and fight off animals as though he's lived in the wilderness all his life. He also occasionally has outbursts of cockiness that seem entirely out of character for him, then he goes back to being kind-hearted. It seems like the writers just didn't really know what to do with him and so they just wrote his character as what it needed to be for the scene without giving things much thought. The odd part is that many of the supporting cast don't suffer from this kind of multiple-personality writing, only the lead.
The animation is a mixed bag. The film opens with some experimental animation using flat colors without any lines, and then switches to a two-tone black & white animation style for the opening credits. After the credits are over, we then switch to the main look of the film, which is fairly standard looking 1980s CEL animation that tends to look only marginally better than TV animation of the era, not being able to stand up to other animated films from that time period in terms of quality.
However, the experimental animation doesn't take a backseat for long, and aside from the other two styles I mentioned, we get a bunch more. For instance, there was a scene where the animation consisted entirely of blue linework on a black background, and you could see the film reel around the edges of the screen. There was another scene where one native tribesman was completely uncolored so you could see the background through him. You might assume this was simply in error, but all of the other tribesmen around him were colored in, and he was uncolored for TWO consecutive shots, which made it seem bizarrely intentional. These different animation styles tend to range from "unique" and "interesting" to "baffling" and "bizarre", but no matter how they come across they really don't tend to add much of anything to the film's overall style, leaving it feeling like the art director just slapped these elements together for no reason at all.
The soundtrack is executed well enough, and sets the tone well. The main theme also sets a nice tone, and was pretty catchy, but nothing that's going to get stuck in my head for hours. The voice actors all played their roles well, and had good delivery on their lines, but there wasn't any breakout performances that would be super memorable. Overall, the audio side of things is well executed, above average, but nothing remarkable.
Overall, Shonen Kenya is an odd film, which seems to try to do too much and, as a result, this ends up being it's downside. There's a decent story buried in here, but all of the stuff around it feels like it was just jumbled together without much thought or care going into any of it, leaving us with a slapdash film that feels bizarre in it's execution and confusing in it's presentation. The main story isn't interesting enough on it's own to warrant such a complicated production, and these bizarre elements only bring it down further and make the bland story more difficult to enjoy... so I'd really only recommend it to people who are simply curious about seeing the bizarre side of the film, anybody else could easily just skip this one.
