You yanks may know this game series as Contra, but in Europe, the games were considered too violent, so the main characters got replaced by robots, and the games were renamed to Probotector. The cover for the first game struck a chord with my love of Transformers-style mechas.
I still remember the first time I viewed the cover for the Super NES sequel, it was a full page ad in a British Nintendo mag, and I´ve wanted ever since to have that cover as a poster, its a case of part nostalgia and part love of TF-style mechas.
While looking for the Probotector covers, I also came across this old Contra ad, I couldn´t help but laugh at the 80esness of it, and wonder just when did videogame companies start using sex to promote their games?
Another early example, and a lovely cover in itself, is this cover for the Commodore 64 version of the old platformer Athena, which has to be one of the first games to have had a female lead.
When it comes to sheer "wow" factor, this NES cover never fails to thrill me:
I can probably think of more covers, but these will do for now.