26. Thor: The Dark World (2013)
Thor was always going to be one of the toughest Marvel properties to get right on the big screen, and The Dark World represents every fan's worst fears about how the God of Thunder and his expansive world could be squandered in movie form.
Despite typically resounding performances from embattled on-screen brothers Chris Hemsworth and Tom Hiddleston, the first Thor sequel is noticeably messy, a tonally jarring mismatch of subplots which never gel with one another or feel in any way thrilling.
Add to these tone inconsistencies one of the series' worst-ever villains and the uninterested performances of co-stars Natalie Portman, Kat Dennings and Christopher Eccleston, and what you have is a film which is nothing more than an enraging waste of potential.