The hunt for easter eggs, references and hidden secrets in films has become an everyday part of the movie coverage machine, one that's grown more and more prominent over the last couple of years.
It's no surprise that one of the most popular film-related communities on Reddit (with almost a million subscribers) is all about uncovering sneaky details hidden in movies: as film fans, we're programmed to love a good treasure hunt, analysing everything from movies to their trailers and even their early first-look images.
Posters are another good place to find cool details and secrets, with one-sheets for all kinds of movies containing well-hidden easter eggs for those with the time - and the patience - to hunt them down. Since posters rarely receive as much attention as trailers or other marketing materials, these nifty tidbits are easily overlooked, making them even more fun to uncover.
But if you've neither the time nor the patience to do so, then fear not! We've gathered some more fiendishly clever examples for you to stuff your eyeballs with. These marketing folks definitely went the extra mile...
Sci-fi war movie Overlord had some really refreshing poster designs, considering that most movies just squash all their characters above a logo and call it a day.
From a giant zombie-fied hand bursting out of a map to several drops of blood that are actually paratroopers falling from a plane, they're all just cool to look at, and a nice change of pace from the generic mainstream fare we usually see.
Not only that, but several of them also contained hidden easter eggs too, which, when uncovered, sent fans on a viral hunt in order to unlock tickets for free early screenings.
The poster at the top of this entry - a man in a helmet against a white background - is one such example. If left untouched the image looks perfectly normal, but if you run it through some photo editing software and alter its brightness and contrast settings (or upload it to your Instagram story and use the Jaipur filter), a previously-unseen URL becomes visible across the middle of the man's face: Instagram.com/InsideTheLab.
This link leads to a real Instagram account, which contains a grid of nine ominous photos. The top-left post (containing a photo of a hook) also has a short video attached, in which one of the movie's cast members invites fans to those free screenings.
This was a nice reward for people willing to do a little bit of extra digging, and though this stunt didn't exactly help Overlord (overall, the film lost money at the box-office), it's great that the studio was willing to give fans free tickets.