Understand. Quoting the correct context is vital. Your sentence as is, is nonsensical : 'similarlities' and 'as previous ones' are the same thing!
The fuller quote is:
...comparatively unfamiliar with the Italian genre.
One can attribute the similarities in this movie as much to previous chanbara.
'as much to' then means, 'equally to'. The similarities in the movie make it as much like the Italian genre as the Japanese chanbara
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