What's inside The Box?
To figure out what is inside Bart Bonte's boxes, you'll have to solve puzzles. I say boxes because there are two versions of the game: a 30 level online version and a 100 level mobile version. (The reason the mobile version has more levels is because those levels use mechanics such as tilting.) Both are free, the levels between the two versions are not all identical, and whatever is inside the browser box is different than whatever is inside the mobile box.
Although this game has been released at the end of May (and maybe you already played it) it's the fun typical of Bonte's games, so no matter what is inside, there still is plenty of levels and fun.