- Author's Saving Throw: The implications that Oliver is still in love with Laurel, and the fact that Laurel, not Felicity, is his ideal lover in the Lotus-Eater Machine, is this for those who felt that Oliver should've ended up with Laurel instead, especially after Felicity adopted the many traits Laurel had in Seasons 1 and 2 that made their initial romance so hated during her romance with Oliver.
- Catharsis Factor: Watching Oliver, Thea, Sara, Diggle, and Ray all beat up on the previous Arrow Big Bads (minus Ra's Al-Ghul) is just SO satisfying on a ton of levels.
- Ensemble Dark Horse: Laura Washington aka Cyberwoman quickly became popular due to her being portrayed by Erica Lutrell from Steven Universe.
- Even Better Sequel: To the previous two Crossovers, to the point that it's widely considered as Arrow's best Crossover episode to date.
- Fridge Brilliance:
- Sara being implied to being a full on lesbian in the virtual world explains why she didn't hook up with Oliver and travel with him on the Queen's Gambit like she did in the real world.
- Meta-example. It may appear jarring that the show's Milestone Celebration is part of a Crossover event instead of a stand-alone episode. But, Arrow is the show that started it all, so the other shows are essentially part of its success.
- Oliver and Sara became heroes after leaving (or at least what they believe is) their perfect world and Laurel behind. In order to finally break free from the Lotus-Eater Machine, they leave their "perfect world" and "Laurel" behind.
- Funny Background Event: A meta example: one of the waiters in the big party scene is played by an actor who clearly decided to make the most of his on-screen time. He is practically dancing with his silver tray full of champagne.
- He Really Can Act: Many reviews from this episode have noted that Stephen Amell gives what is probably his best performance to date in this episode.
- Thea refusing to leave the Lotus-Eater Machine for about ten seconds before changing her mind. It appears to only exist because they needed some kind of dramatic act break.
- Wild Dog blaming Supergirl's appearance for the Dominators' appearance, despite the fact that she was brought to their Earth to stop the Dominators after the heroes ended up finding out about their existence.
- Related to both of the above, Wild Dog's grudge against superpowers lasts for pretty much no time and is resolved ridiculously easily. This is compounded by the fact that he didn't seem to have any problem working with Ragman.
- The scene where all of Oliver's dead loved ones appear to encourage him to leave and be strong while touching and emotional seems rather out of place given that he was already leaving, and the world is supposed to be engineered to prevent him from leaving.
- Special Effects Failure: Tommy and Roy's "ghosts" that appear before Oliver leaves through the portal are obviously C.G.I used from old footage as their actors were unavailable.
- Surprisingly Improved Sequel: Compared to Arrow's side of the Crossover from the previous year.
- They Wasted a Perfectly Good Character:
- Slade is the only returning Big Bad who has no lines whatsoever and whose face is kept hidden, for the obvious reason that his actor Manu Bennett didn't reprise the role.
- Cyberwoman could've made more of a threat if she hadn't debuted in a crossover involving aliens and where she's curb stomped by Flash and Supergirl in a matter of minutes. Given that she's also an Expy of Cyborg's Evil Distaff Counterpart Cyborgirl, some feel he should've been introduced before including her in any capacity.
- They Wasted a Perfectly Good Plot: The final part of "Invasion!" feels very rushed, with several key characters missing from it with no explanation. That could've been avoided if this episode had been used to develop the main plot of the crossover, instead of devoting most of it to a clichéd Lotus-Eater Machine scenario that has little to do with the rest of the story.
- Win Back the Crowd: This episode proved largely popular, due to the returning characters (especially Laurel), its connections to the other series as part of the 2016 crossover, and its retrospective nature.
YMMV / Arrow S5E8 "Invasion!"