Cisco refers to Savitar as "Two-Face" after he was rescued by Gypsy. This is a tongue-in-cheek reference to the comics villain Harvey Dent, aka Two-Face, an antagonist of Batman who also has the left half his face severely scarred.
The scene where Savitar holds Cisco while vibrating his hand and telling him that he will die "the same way twice" refers to his death in the erased timeline in Out of Time.
Savitar is killed the same way The Rival was killed in Flashpoint. The Rival was shot in the back by Joe as he was trying to attack Barry from behind, and Savitar was shot by Iris when he was trying to do the same to Barry.
In the previous episode, Wally fought Savitar and injured his knee. However, in this episode Wally is still able to run /walk. This may be related to 2024 when Wally was in a wheel chair.
In the previous episode, H.R.'s last word to Cisco is "Till next time" and salutes him after he put his hat.
However, in this episode the flashback shows it was changed to "Till the next one" and H.R. slightly tip his hat.