Justin Hullinger’s review published on Letterboxd:
Watched the extended cut this time around, where the only differences I noticed was a flashback scene between Harley and The Joker where she's frustrated over all of the ways she's proven her love to him, and a brief +/- 30 seconds of Deadshot and Flag talking on the carrier helicopter.
So, yeah, the movie's still terrible. There's still nothing here to explain why Harley fell in love with The Joker, or why she moves in and out of a Brooklyn accent. Licensed music bludgeons you over the head for the first half, and the first 20 minutes is probably the laziest setup for backstories that I've seen in a big movie.