You know, good or bad, a review with a link to his site raises his google ranking... so he wins either way.
But giving away a free copy in exchange for an unbiased review isn't that bad of a marketing idea.
'unbiased' is the keyword here.
Plus a bad review lets him know what to improve.
And the eyes of a developer isn't the same as a user, so a review from a user is much more useful, since you code games for users, not other developers.