Slaanesh, the God of Rape and Cocaine, has evil Space Marines who murder people using the power of Heavy Metal. They literally have guitar flamethrower guns. Back in the 80s the game was so obviously over the top and silly that it was hard to take seriously. The Space Orks talk, dress, and act like British football hooligans. They've gotten more serious about the Grim Dark since then and it's made it harder to read as satire.