New games journalism is explained in the place of the player, the journalist will explain what he did, how he felt and what happened during his play through.
Old games journalism is explaining the game piece by piece, feature by feature, for example they journalist will talk about the mechanics, the graphics, the gameplay, the bugs etc.
I feel that both new and old games journalism are helpful, but to different audiences. New games journalism is more for the consumer, the person buying the game. They want to know what you will get out of the game.
However old games journalism is more for games designers or people interested in certain aspects of the game.
