lessen the overall impact the movie could have had 
(ROOT (S (VP (VB lessen) (NP (NP (DT the) (JJ overall) (NN impact)) (SBAR (S (NP (DT the) (NN movie)) (VP (MD could) (VP (VB have) (VP (VBN had))))))))))
(ROOT (S (VP (VB ) (NP (NP (DT ) (JJ ) (NN )) (SBAR (S (NP (DT ) (NN )) (VP (MD ) (VP (VB ) (VP (VBN ))))))))))