The problem with HD updates is that even if they're well-made they only ever improve the game enough to make it look as good as you remember it – such is the power of a good pair of rose-tinted spectacles.
Tons of content and given Contract's semi-remake status one of the more complete HD collections around; Lots of imaginative, and often darkly funny, set pieces
Silent Assassin is a decade old and it feels like it, with clunky control, inscrutable AI, and lots of trial and error; Visuals are only slightly improved