Here is my ranking (from least favourite to most favourite) of the films within the Species franchise, with a short explanation accompanying each:
#4 – Species: The Awakening (Species 4)
There is nothing wrong with deviating from previous installments yet staying within the same ‘universe’, but promotional material varies for this installment to include/not include ‘4’ in the title. The only connection to previous installments is the alien DNA, which is interestingly explored. However with the amping up of the cloning and body transfer (alongside different different alien designs) it could almost be a stand-alone film. For this, it is last.
#3 – Species 2
My main issue with Species 2 is that it doesn’t follow logically from the end of Species; we see a rat become infected and mutate. I understand that a rat/alien hybrid isn’t as sexy as Sil, but it would spread exponentially and could lead to humans being infected, as well as other species. It would be an interesting premise. That being said, the route they chose allowed for the return of Natasha Henstridge and in a way answered the question of what if they didn’t kill Sil at the end of the original. Picking up the alien DNA from Mars at the same time that they make Eve is too coincidental and the male hybrid form is so different from the female that it aesthetically makes little sense.
#2 – Species 3
Unlike it’s predecessor, Species 3 picks up exactly where Species 2 ends. How they do so is either ingenious or clutching at straws, though I personally liked it. What I also liked was that it does not ignore what has come before it at all and the effects of the action in Species 2 is a driving force in the narrative of this sequel – in the vain of the quarter-breeds, or whatever they refer to themselves as. I also like the questions that it raises and the fact that it attempts to develop what hybrids are and how they are motivated. In light of its predecessors, there’s also a nature/nurture subplot. Though the alien design does deviate from Sil/Eve it’s not as drastic as the difference between male and female hybrids seen in Species 2, so it aesthetically fits.
#1 – Species
What quite possibly makes the first film the best within the franchise is that it is original and is not confined to (or wanting to break away from) any plot points or ‘facts’ from predecessors. In Species 3 and 4 the hybrids are raised within society, as opposed to in a laboratory in Species and Species 2. You could say that the latter half of the franchise raises a question of nature vs nurture – to what extent we are defined by our DNA and our environment. With the first two installments however it is the question of to what extent is our own DNA driving Sil/Eve – is it the human or alien DNA that feeds the desire to reproduce and kill? Though this has the nature/nurture connotations, it is, in the original more than 2, used for fear and horror. It is the fear of tampering with nature. The fear of the unknown. The fear of ourselves.