Despite high-tech special effects of today's violent horror movies it does not create the emotional impact it did on the classic horrors films of the early 1900s.

2 answers

Is this a good thesis statement
Essentially it's a good thesis statement.

However, since the antecedent (effects) is plural, the pronouns that refer to it should also be plural.

Despite high-tech special effects of today's violent horror movies THEY DO not create the emotional impact OF THE EARLY 1900s classic HORROR films.