- Ass Pull: Time wraiths have never been mentioned before, even on the time travel heavy Legends of Tomorrow. Apparently it was just pure luck that they never appeared before now, along with the fact that they seem to specialize in speedsters manipulating the timeline.
- Author's Saving Throw:
- Harry sharply corrects Barry for calling Thawne "Wells", finally having someone address the Fridge Horror regarding the Fate Worse than Death of the real Earth-1 Wells after Eobard Thawne's Dead Person Impersonation.
- Hartley becoming a good guy via Cosmic Retcon after complaints about him being a pure villain last season.
- The explanation that Thawne was artificially boosting his speed via tachyons to exceed Barry's, for those that felt Barry being called "the fastest man alive" was being undermined. Without it, Barry ISN'T slower than Thawne.
- Narm Charm: Eddie's "birthday" message is up there with Gwen Stacy's graduation speech as an overly on-the-nose pre-death statement. Unlike with that one, however, Barry instructed him to speak to Iris as if it was the last thing he'd ever get to say to her, so it's more than a little justified.
- They Wasted a Perfectly Good Plot:
- After Barry rewrites the timeline, nothing really changes except Pied Piper being a guest member of S.T.A.R. Labs. Justified because that's not really something you can afford to do on a TV show.
- Pied Piper's HeelFace Turn, which would've had a greater emotional impact if we had actually seen it develop on screen, instead of offscreen.
- Considering how the Supergirl Crossover takes place after this episode, many viewers assumed we would see Barry putting on the tachyon device before running fast enough to break the barrier. Doesn't happen until next episode.
- What an Idiot!: Barry's plan is not very well thought out in the first place, and that's not even getting into his execution of it. Even Thawne facepalms at the attempt and just shuffles him back to the future before he screws anything else up.
- The Gag Reel even has Grant Gustin, Barry's actor, question the logic behind Barry leaving his past self unconscious in an open alley.
YMMV / The Flash (2014) S2E17 "Flash Back"