Film regularly shown got better (8)
I believe the answer is:
improved
'got better' is the definition.
(I've seen this before)
'film regularly shown' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'shown' becomes 'proved' (proving is a kind of showing).
The alternate letters of 'film' are 'im'.
'im'+'proved'='IMPROVED'
(Other definitions for improved that I've seen before include "Grew or made better" , "Made progress" , "Became better" , "Made or got better" , "Made better in quality" .)