Well I’m certainly looking forward to next season. 
Kelly’s appearance was a little underwhelming, but I loved Eichhorst being abruptly summoned. I really want to see where they go with this war between The Master and the other Ancients.
I liked the backwards-walking bit. Though given how derivative of other works the elements of The Strain seem to be, I wouldn’t be surprised to learn that the interesting-looking retreat was borrowed from something else.
(For example, the “competing factions of ancient vampires clash with each other over the tending of the ‘herds of humans’ on which they feed” storyline was used in Whitley Strieber’s 2001 novel The Last Vampire, which was a sequel to his more famous The Hunger. Whether it was original in 2001, I don’t know, but it’s certainly not original in The Strain.)