Normally, when it comes to acting, so long as you fulfill the most basic bulletpoints for what they're looking for in the part you're auditioning to get, your acting skills can carry you the rest of the way. But comic book adaptations are a tricky sort that add in a lot of extra qualifiers onto that already stressful process.
Unlike with regular books, where describing your lead character in painstaking detail is frowned upon - leading to the reader filling in the blanks of what the writer deems to be irrelevant to describe, people KNOW what Peter Parker looks like, and have known for a while.
And it isn't just looks, you also have to nail their mannerisms, their quirks, their ideals, in every action you take, or the nerd brigade will eat you alive.
So as one can imagine, not every actor, regardless of talent, is fit for every part. Whether because they know nothing about the character, are too recognizable to blend into the role, or because their acting style is just wrong for the character, these are the comic book movies that made one casting choice that brought the whole house of cards crumbling down.
10. Shaquille O'Neal As Steel - Steel
This one is at the bottom because Steel has a lot more problems with it besides the casting of its central character, but casting Shaquille O'Neal definitely didn't help matters.
Shaq is an icon, but he definitely was never the best actor in the world. And Steel is one of the biggest examples of his weaknesses as a performer.
As a character, John Henry Irons is a brilliant but easygoing scientist who looks up to Superman so much that he eventually crafts his own iron man-like suit from scratch to fight crime with.
But in the hands of Shaq, pretty much all of that charisma and charm that Irons is supposed to embody is lost in the void that is his monotone performance.
Even at his prime in the mid-90s when this came out, Shaq was just a fundamentally bad pick for this character, and hopefully DC learns their lesson on this front whenever they finally get around to giving Steel another shot. As much of a pipe dream as that prospect might be.