One of the biggest noticeable differences between Japanese and American box art for Kirby games is how Kirby himself is portrayed. Often in Japan Kirby is shown with wide eyes and a certain cuteness, while in America he’s often given weapons and angry eyes to accentuate his serious side. This divide has been pretty clear for a long time, even going so far as to have a TV Tropes page dedicated to the differences.
HAL Laboratories director Shinya Kumazaki explained that Japan loves the cuteness of Kirby, while Americans prefer their pink puff ball to look a little bit more serious.
“For the Japanese versions we are, at [Kirby series developer] HAL, involved in everything throughout development, including the package design. The most powerful image of Kirby is that cute image, we think that’s the one that appeals to the widest audience. While it does start cute, we know there is a serious side to Kirby as well, and throughout the gameplay we see more and more of that, and the games themselves have quite a bit of depth.
That being said, we recognise that Kirby’s cuteness is his biggest draw in [the Japanese] market. What we have heard is that strong, tough Kirby that’s really battling hard is a more appealing sign of Kirby, so that’s what we feature in the US.”
Apparently, Americans really do love violence more than cuteness.