Hidden levels, messages, cheat codes and shortcuts have been a part of playing video games for as long as video games have been around. One of the first famous examples was in the 1979 Atari game "Adventure," whereby the game's programmer, Warren Robinett, had created a hidden room where his name was written.

As a recent article in New Scientist points out, gameplay secrets like these are often referred to as "Easter eggs," and over the years they've grown more and more elaborate. Take, for instance, the 2009 stunt bike game "Trials HD," whereby mathematical patterns and cryptic messages discovered in the game’s more hard-to-reach places turned out to reveal a bit of DNA code. A host of other mysteries in the game, including a number of Leonardo Da Vinci references, ended up alluding to a grand puzzle far larger than the game itself.

As some players have noted, the search for Easter eggs in "Trials HD" amounted to the video game equivalent of reading a Dan Brown thriller.

The 2012 follow-up to that game, called "Trials Evolution," took Easter eggs to another level, even spilling over into a real-life treasure hunt of sorts. After years of investigation, a few dozen hardcore gamers had uncovered clues and coded messages in the game that turned out to reveal GPS coordinates for four buried boxes in Helsinki, San Francisco, Sydney and Bath in the United Kingdom. Inside each box (yes, they really ended up existing!) was a golden key and another clue: that the keys could be used to open another box "Underneath the Eiffel Tower" wherein the final solution would be given. The only catch was that this box would only appear midday on Aug. 1 in the year 2113.

The discoverers of those keys plan to pass them along to their descendants so that the puzzle can be carried out to completion. (The game developer behind the puzzles, Antti Ilvessuo, claims to have made specific arrangements for next century’s big reveal, as even he won’t be alive to see the finale.)

Another series of games known to contain elaborate Easter eggs is "Battlefield." For instance, within the "Battlefield 4" game, one player found a skull symbol on the back of a random pillar. Nearby the skull, a lantern seemed to blink erratically. Eventually, some clever gamer realized that the blinking pattern was actually Morse code, which kicked off an Easter egg hunt that eventually culminated in a secret special outfit that could be unlocked for the game's character.

This puzzle solution might not seem as profound as the one in "Trials," but as many gamers admit, the journey is more valuable than the destination. The satisfaction of having solved such an elaborate puzzle is its own reward.

You might even argue that these puzzles are more satisfying than reading a Da Vinci Code-esque mystery novel, because instead of reading about the story's protagonist solving the puzzles, gamers are the active participants and they must solve the puzzles themselves. It's a level of gaming that most video game players never reach, so those who pursue these puzzles are also members of an exclusive club.

“You’ll be daydreaming about it on the train and thinking about it at night,” said Brad Hill, a gamer who has had a hand in finding Easter eggs in both the "Trials" and "Battlefield" games. “Some days, your mind is just messed up. It’s been amazing.”