There were certain aspects to this episode that I thought were quite original and that helped elaborate Spike's character, but there were others that I thought were unfortunate and that clashed with what was established in the films.
In particular, I like how they seem to imply that Spike is just as intelligent as the others (or at least in the same range) but that he simply views the world in a fundamentally different way. His fixation on things that the others may not notice or may find unimportant (the song of the plants) and his inability to communicate effectively would seem to make Spike almost autistic in his worldview and perceptions. I feel that the portrayal of a character in this way is rather original and may actually be useful to the target audience of young children. In the films we have seen many different physical 'kinds' join together and become friends despite their differences, whereas in this episode we get to see much of it through the eyes of someone who is of a different 'mental' kind. As someone who is on the autistic spectrum with rather mild traits, I appreciate the attempt to portray a character who is 'different' mentally. It is something that is often ignored in the popular media or otherwise is portrayed from a third person perspective.
However, there were many parts to this episode that I did not care for at all. First of all, they portray Spike as not understanding the rest of the gang, only understanding certain words such as personal names and food names. This clashes with many incidents in the films where Spike would nod, shake his head, or give affirmative grunts to indicate his understanding of entire conversations and complex ideas. For whatever it is worth, I will be portraying Spike as if he is simply mute (as a leafeater) but can still understand language in the 'sudden change of species' roleplay. Where the films and the TV series contradict, I choose to have the film's portrayal take priority.
Secondly, the whole 'song of the plants' idea could have been done better by depicting Spike as smelling a symphony of smells. It was already established in the series that Spike has a well-developed sense of smell, so why not use that as a plot point in this episode? I simply view that as a lost opportunity to established continuity with what came before. Although, as Cancerian Tiger pointed out earlier in this topic, his hearing of the 'song of the plants' could be due to synesthesia, where he is 'hearing' smells due to a misrouting of sensory information through his thalamus. If that is the case, then my criticism on that point would be unfounded.
So, overall I have mixed views on this episode. I appreciate what they were trying to do in their portrayal of Spike, but I feel that they unnecessarily created continuity errors with the films. Although, admittedly, continuity issues are nothing new in the television series.
