Violent opening to film intimidated emotional reviewer called Ebert (6)
I believe the answer is:
fierce
'violent' is the definition.
(I know that violent can be written as fierce)
'opening to film intimidated emotional reviewer called ebert' is the wordplay.
'opening to' suggests taking the first letters.
The initial letters of 'film intimidated emotional reviewer called ebert' is 'FIERCE'.
(Other definitions for fierce that I've seen before include "Aggressive; intense" , "Ruthlessly violent" , "intensity" , "brutal" , "Ferocious, savage" .)