Here's one that everyone tends to forget when discussing gory games: Creatures. Twisted stuff, this! And we cannot forget Techno-Cop and Mortal Kombat.
And if we wanna delve into the PD world, there's The Texas Chainsaw Massacre (not graphic, but it's the thought that counts!), Schoolyard Slaughter, and a sick pair of text adventures, Bleed - A Journey Through Violence and its sequel Bleed II. And there's a bit of gore in the Zombie Apocalypse series, as well.