🚨Warning: Spoilers for Season 1 ahead!🚨
1. First, when Nadia is investigating the building, you can see that she has a cup of sliced watermelon. This is before we learn that when Nadia was younger, her mom would buy lots of watermelon.
2. During one of the birthday parties, Maxine calls Nadia a cockroach. Later, Nadia describes the time loops as a "bug in the code," so Nadia could be the bug in the system.
4. Later, we learn that Nadia's video game that Alan claims is impossible is also named "The Legend of Ariadne."
5. Nadia buys cottage cheese at the bodega during Episode 1. This is before she tells Beatrice that cottage cheese helps her maintain her figure.
6. While it's unclear what it could mean, chicken is oddly an important part of Russian Doll — Maxine cooks a chicken at the birthday party, John gets chicken before meeting Nadia, and of course, one of Nadia's deaths is caused by her choking on a chicken bone.
7. The three guys Nadia meets in the bodega actually appear more than once and seemingly as different characters. They're seen in the bodega, at Nadia's office, and as EMTs.
8. Also, one of the guys always mentions his mother whenever Nadia runs into them — this could be related to Nadia's unresolved issues with her own mother.
9. In Episode 1, you can see that Horse isn't wearing shoes, something Nadia doesn't notice until Episode 3.
10. In Episode 3, you can spot Alan walking through Tompkins Square Park, this is before Nadia meets him in the elevator.
11. At Ferran's bodega, he has an advertisement for "Yep" on the counter. Later, Nadia uses "Yep" to track down Alan after the jewelry store.
12. The old man that lives in Alan's building tells him, "Women don't like to take the stairs. This alludes to Nadia's deaths on the apartment stairs.
13. In Episode 1, you can spot the red scarf around the girl Lizzy is making out with. In the final episode, she gives the scarf to Alan.
14. In Ruth's house, you can spot a picture of Ruth and one of her dead husbands. The picture is actually of actress Elizabeth Ashley, who plays Ruth, and her second husband George Peppard.
15. In the book Emily of New Moon, Emily, an orphaned girl, has an Aunt Ruth, who is Emily's ally in times of trouble — Ruth remains Nadia's closest confidant throughout the series and acted as her surrogate mother.
16. In Episode 1, Mike is actually talking to Beatrice on the phone. He references the vacation that Alan and Beatrice are supposed to be going on.
17. Mike hits on Nadia while discussing John Updike, an American novelist. Later, we learn that Beatrice is doing her dissertation on Updike.
18. In Episode 2, one of the bodega's customers changes his last lottery number from 21 to 22. There are 22 deaths in Season 1.
19. You can spot Nadia's mom wearing the necklace during the flashback episode.
20. The person that tried to steal Horse's shoes at the homeless shelter appears in the final episode when Alan is giving Horse all of his money.
21. And finally, during the final scene where Nadia joins the parade, you can actually spot two other Nadia's walking past her.
