When Sonny is speaking to Mobius Command around the 39:00 minute mark, he mentions "Operation Riverrun." This is a reference to James Joyce's "Finnegan's Wake," (1939). The last sentence of the novel is a fragment, and completes the first line of the novel, forming a closed loop. See more

Goofs

Ren and Hannah discover the ring of petrified grass outside the house and make the statement that the time loop is contained to only inside the perimeter of that ring An aerial shot then shows the ring going around the house, hence the boundary of the time loops. When Sonny calls Torus for extraction, they are outside of the time loop and would be getting hundreds of calls. See more