Rockford Then And Then

The game was largely the same, but the portrayal of Boulder Dash's hero Rockford changed quite a bit between 1985 and 1990.  In-game, Rockford was a rather blocky, insectoid-looking fellow in his original incarnation, but he was portrayed as a red-haired, big-eyed, tomato-headed kid on the 1985 MicroFun box (with artwork by the ubiquitous Scott Ross):

By 1990, Rockford had become a blonde, chiseled Indiana Jones variant in JVC's ads for the NES version:

Same game, different target demographic.  Adults in 1985 wanted to put their cares aside and play like they did when they were kids, while kids in 1990 wanted to take on more serious challenges.

The fact that both audiences could get what they were looking for out of the same product is part of what makes gaming great.

It also makes game marketing fun to watch.