Shallow Grave (Danny Boyle, 1994, UK)
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Average user rating: 7.4/10
My rating: 9/10
Very dark, but the perfect thriller. Set in Edinburgh and concerning three flatmates (Christopher Eccleston, Ewan McGregor and Kerry Fox), whose new lodger is found dead in his bedroom with a huge suitcase full of money under his bed. They decide to keep the money and dispose of the corpse, obviously with some rather sinister consequences. Perfect acting, perfect atmosphere, perfect cinematography, perfect plot twists...
Bought on DVD after I saw it on TV many moons ago and was massively impressed.