At 36:30 the woman talking on her mobile once again passes in front of Central City PD as she does in almost every episode.
John Wesley Shipp (Henry Allen) previously portrayed Professor Zoom in Batman: The Brave and the Bold (2008).
When Iris states that even "in blackest night" there still remains hope is a nod to the Green Lantern mantra: "In brightest day, in blackest night, no evil shall escape my sight. Let those who worship evil's might, beware my power - Green Lantern's light!" The Earth-2 metahumans definitely fit into the category of worshipping the nefarious Zoom.
When Cisco sees a lot of dead and dying birds he says that he feels like he's in a Hitchcock movie, precisely "The Birds" .