I agree with Darryl. The game you gave a link to gave both the score and the number of boxes which were eaten. But I guess if you can eat all the boxes, the overall score becomes rather redundant doesn't it.
Also, I think there should possibly be some method of insuring that everyone's game area has the same number (roughly at least), of numbers ... I mean 18*18 sure, but the values of the cells is what I mean. If someone had a box full of 6's, they would be rather more likely to get a higher score than if they didn't. That is if the idea started by Darryl is implemented. But the tough choice is how to judge the score if both are to be taken into account.
Just by doing a quick test, it gives the score by: summing up the number of every box you eat, and multiplying the result by 10.
