I agree that Donkey Kong and Mario are very similar, but I think that this was done on purpose. Nintendo knew the fame that the Donkey Kong game had with consumers, so they realized that this type of platform game was what people would spend money for. Another reason for them being similar is that the Mario game came out of the Donkey Kong game – this was almost like a sequel, having the same character with the same objective.
Even though there might be different elements to the games, I see your point on how it is as if they have different skins. But, I do not agree fully on that point. We saw in class how there were many different versions of Tetris, but they are all essentially the same game. Yes, Mario and Donkey Kong are both platform games, have the same characters, and the same objective, but the way of playing is different. In Donkey Kong all you do is move Mario around by climbing ladders and jumping over the barrels. In Mario, you have many more obstacles, there are extra ways to earn points and lives, there is an actual world that you can explore, and your character can change. I think that there are many more differences than similarities between the two games.