While this is the 100th episode, this episode has a lot of references to earlier seasons, such as a reference to the first scene of the whole series and Rick's (Andrew Lincoln) first walker kill (this episode shows an identical walker and identical place). It also has a reference to Carol's (Melissa McBride) famous flower obsession "Look at the flowers" (She looks at a flower drawing on a wall beside her).
Greg Nicotero directed this episode. This marks the fifth time in a row, that Nicotero directed a season premiere. Nicotero also expressed his deep excitement about directing this episode, because this is the 100th episode of the series. Nicotero described it as it being "a dream come true."
This episode is dedicated to George A. Romero and John Bernecker. Romero for being one of the first pioneers and writers of modern zombie and horror stories and movies. Bernecker, a veteran stunt performer, died after a fall on a concrete floor in July 2017.
The scenes where you see Carol and Tara on lookout for Walkers on the highway each time Tara checks her watch it's shows pretty much the date except for the month and year. First time she looks at her watch it says Wed 3 and the 2nd time she looks at her watch it says Thurs 4, those scenes where shot during the first 2 days of filming for Season 8. May 3, 2017 and May 4, 2017.
After the opening credits, there is a scene with Carl (Chandler Riggs) stopping the van he's driving to look for gas. The scene plays out exactly like the very first scene of the series, with Rick (Andrew Lincoln) looking for gas, too. It then continues with Rick meeting Carl, where a dead girl shows up as a walker. The actress playing that walker is Addy Miller. She was also the one playing the "little girl"-walker, that Rick shot in the pilot that aired in 2010.
The fair Alexandria puts on in the comic volume Whispers to Screams is hinted at the end of the flash forward and the flash forward is more likely to be showing Rick (Andrew Lincoln) and Alexandria's New Beginning after All Out War.
In the first episode of season 7, Negan goes to apply a tourniguet to Carl's arm and asks if he is a southpaw, someone that uses their left hand. Carl replies that he is not. However, in the gas station scene, he can be clearly seen holding the gun with his left index finger on the trigger.