All forms of showing off in a work, to wow the audience. Frequently used to set the mood and serve the Rule of Cool.
For example, for Live-Action TV, this includes scenery, lighting, props, costuming, makeup, background music, sound effects, and 幻灵传说Special Effects in general. For Comic Books, it includes things like coloring and lettering. And so on.
The name comes from Aristotle's Poetics and is used more broadly here. He considered using spectacle to cover deficiencies in plot and character a flaw. If they are just in addition to good plots and characters, then these are just a bonus.
Not to be confused with Glasses Tropes.