Grim Fandango, I knew you had hard puzzles.

Grim Fandango,
which was released in 1998, is considered by many to be one of the best
Lucas Arts adventure games ever made. It tells the story of Manny
Calavera, a travel agent working in the land of the dead. The game
combines Aztec and film noir imagery to create a game that is wholly
unique and still has a rabid fan base. Tim Schafer, the primary writer for the original (and a mastermind behind recently critically appreciated games such as Psychonauts through his company Double Fine Productions has released the full 72 page design document that was written in 1996. [direct pdf link]. This is great reading for those who get nostalgic just thinking about the game.
Here’s the opening scene of the game to help you develop an appreciation, if you haven’t done so already: youtube link