Greg Costikyan on Play This Thing!
A review is a buyer's guide. It exists to tell you about some new product that you can buy, and whether you should or should not buy it. A good review goes beyond that, and suggests who should buy it, since not everyone enjoys everything. (E.g., A romance novel may be very fine of its kind, but is quite unlikely to appeal to me, since it is not a genre I enjoy.)One of the first things I do in my Video Game Culture and Theory course is have students compare a games magazine review with a "new games journalism essay" (in order to get them to realize how much else there is to write about besides simply reviewing the game for a person who has never played it). I then introduce games scholarship, and have students write their own academic research paper on games. The first time I taught this course, in 2006, there was plenty of scholarship of the kind Costikyan calls for, and when I taught it again in 2008, there was so much that perhaps next year I will demote the importance of "new games journalism" and jump right into the criticism.
Thus, Ebert is, ultimately, a reviewer; the net result of his discussion of a work is a thumbs-up or thumbs-down. Mind you, he is also an informed and intelligent watcher of film, and his discussion of a movie frequently veers in the direction of criticism; but he is not being paid to write critical works. Pauline Kael was.
Criticism is an informed discussion, by an intelligent and knowledgeable observer of a medium, of the merits and importance (or lack thereof) of a particular work. Criticism isn't intended to help the reader decide whether or not to plunk down money on something; some readers' purchase decisions may be influenced, but guiding their decisions is not the purpose of the critical work. Criticism is, in a sense merely "writing about" -- about art, about dance, about theater, about writing, about a game--about any particular work of art. How a critical piece addresses a work, and what approach it takes, may vary widely from critic to critic, and from work to work. There are, in fact, many valid critical approaches to a work, and at any given time, a critique may adopt only one, or several of them.

