The phrase "astonishingly dramatic" is correct and usable in written English.
It can be used to describe something that is surprisingly intense or impactful, often in a theatrical or emotional context.
Example: "The film's ending was astonishingly dramatic, leaving the audience in stunned silence."
Alternatives: "incredibly dramatic" or "remarkably dramatic".
It was an astonishingly wonderful, dramatic and beautiful place whose influence was only limited because St John's Wood is a lush backwater.
If nothing else, Inherent Vice proves that Joaquin Phoenix is not merely an astonishingly gifted dramatic performer but also a physical comedian on par with Jim Carrey and Chris Farley.
With astonishingly intimate and unique access, this film tells the dramatic, unfolding story of the demise of one of Britain's best-known charities and the ultimate fall from grace of its founder Camila Batmanghelidjh.
The dramatic playing field of the Superman story is astonishingly narrow.
But astonishingly Accies responded with a goal from Morris and a dramatic equaliser from Gordon six minutes from time.
It's one of Godard's most grandly dramatic (even classically melodramatic) films, and, at the same time, an astonishingly modernistic work of audacious form and content.
The plays and poems represent everything: a complex worldview, an astonishingly varied sense of character and tone, a command of poetic form and rhetoric and dramatic structure.
Student protests, Soviet might, assassinations, war and famine - although these dramatic events took place more than a generation ago they seem incredibly immediate and astonishingly relevant today.
As a young newlywed and recovering addict living in the creaky rural home where she grew up, Ms. Lodge (astonishingly, in her first film) throws herself into a character required, more than once, to perform tense, dramatic scenes while totally naked.
