The train scene was filmed in Belgrade, Serbia. The train did not need any "make-up" as the train operates in this condition regularly. The underground station was made for a metro line that never has been finished.
This movie was shot in Belgrade, Serbia, over 40 days.
The film was originally produced by Universal for a nationwide theatrical release, but was instead offloaded to Netflix for an undisclosed amount.
Lizzy Caplan's (Alice) real life husband, Tom Riley, plays Chris the Wellness Centre Patient that warns Peter.
This is not the first alien invasion film that Lizzy Caplan has starred in. She also starred in Cloverfield (2008), which was also about an alien invasion but with one giant Godzilla-like monster taking over New York City.