12 Biggest Retcons In The Marvel Cinematic Universe
4. Hydra (Or S.H.I.E.L.D.) Hasn't Really Been Destroyed
Following the big Hydra reveal, The Winter Soldier essentially saw S.H.I.E.L.D. destroyed and the remaining Hydra cells forced underground. What followed in Avengers: Age Of Ultron seemed to wrap that up, with dialogue suggesting the assault on Strucker's base was the final step of Hydra take-down.
Yet just a couple of months later in Ant-Man we saw Scott Lang trying to stop Darren Cross from selling his Yellowjacket tech to Hydra. To the movie's credit, it did set Mitch Carson up as a double-agent who once worked at the top of S.H.I.E.L.D., but that couldn't distract that it was undoing something two movies had put serious time into tying up. This isn't as crazy as some, sure, and has precedent in the TV series (although, as we've already established, that's barely canon), but it's still poor synergy.
The same is also true of S.H.I.E.L.D., to a slightly lesser degree; Age Of Ultron's finale saw Nick Fury return with a fully staffed helicarrier and later movies have seen the U.N. take up an almost identical role. More plot contrivance than straight-up retcon, it's still rather irritating.