Weird ending to the series. The aliens seemed to serve no real purpose to the series, like the creator thought "I want aliens!" and regardless of the fact that they didn't fit in just shoehorned them in.
It lost coherency quite a bit toward the end, I think the series would have benefitted from zero alien bull but there you go. I did rather enjoy the last episode and how it tied it all off (apart from the aliens coming again!)
Nothing to do with cancellation though, it has already been renewed ages ago for a third season.