How NES Box Art Were (In my Opinion)

From what I saw (through the internet), most NES box art look realistic, or, in other words, bad-ass. It looks like the art would be for a cover of some "epic", action-packed movie, but probably back then, it was a way to represent what the game is (or to mainly get consumers to buy the specific game). To contrast, Super Mario Bros. had a simple box art showing Mario's sprite in it, which gives the idea of what the game will look and might be like. For Ninja Gaiden, however, its box art shows a ninja with a burning city in the background, representing how awesome the game will be, but not what it will look like in the game. So basically, Super Mario Bros.'s box art sticks with the spirit of the graphics itself, while Ninja Gaiden's box art went to more of a movie look  to make itself more appealing to the consumers. I'm not saying they're bad, just that some bad-ass box art were too emphasized. But, I do like them though. I guess it was a way to get them on the market.