I'm not sure I understand. You don't need anyone's permission to review their game. As far as I am concerned you would only need to ask permission if you wanted to host their games on your site. So if someone says no, then don't host their game, but you can still do a review of it, with a link pointing to their site/download or whatever. Now if they are charging $$ for the game, and are refusing to give you a free review copy, that's different. In that case you would have to buy it, and then review it.
And if they don't like the reveiw, well that's just too bad. They put the game out there, and you are free to write what you think about it, good or bad.
~Zenassem