In 10 Cloverfield Lane, Emmett notices that the puzzle was not complete. The cat's eye puzzle pieces were missing:
I felt like it was some foreshadowing but didn't get it. Did I miss something? Is there any significance to the missing puzzle piece?
The answer got revealed in ARG, from postapocalypticmedia.com
John Goodman’s character Howard Stambler, as twisted as he is, is also something of a romantic. You see, he knew that the world was in trouble, and made careful preparations for his estranged daughter to find him once the shit hits the fan.
One of the preparations involves an ammo box that he buried in a field. He filled it with several useful items, a handwritten note, and two puzzle pieces: These same pieces, it turns out, are the ones the movie protagonists spend time looking for.
Even the user uploaded a detailed video later: