almeida67 wrote :
You have a promotional site, or a game, you must define your choice, definitively.
I quite agree with this. Personally, I don't see the concept of a combination of the two working. For one, I expect that either way one of the two isn't going to keep up: either there are not enough updates to the game-aspect to keep it interesting, or there are not enough games around to keep the game-aspect going (i.e. too little xp to go around).
But more importantly, you are effectively bribing your users into giving comments. Now, the less time they spent writing comments the higher the reward is. Logic result: low-quality comments, they are not written by someone who actually wants to inform other users, they're written by someone who wants to finish the game-aspect of your site. In order to get useful reviews either the comments need to be highly moderated (no xp for useless comments, but who's to define what is useful...), or the 'bribe' needs to be second place to giving useful reviews (and I honestly have no idea how you would go about doing that).
While I do think there might be a need for a proper community-based games site (with proper reviews, classification into categories, detailed ratings (graphic/gameplay/etc.), etc. etc.), I don't think this is the way to go about that.