I did, I used Keymailer.co but only the free tier. There were a few reviews that came out of that but not much. I don't think it contributed much to sales. If your margin is high enough for your game then you might justify paying a bit of money to access some more features. I just couldn't do that with my margins.
Another thing that you SHOULD do is get active on indiedb.com. Make a profile for your game and then do a giveaway to get some exposure. I did a 200 key giveaway and I noticed a sales boost after that. I actually did the giveaway hoping for reviews, but I didn't get any reviews out of it. Still, for my next game I'm going to have a much louder presence on indiedb. You might also look into gamejolt.
Also - make a google analytics account now and wire it up to your store pages BEFORE you start selling and marketing. It will give you good alternative insight to your campaigns.
Good luck with your demo :)
Thanks for the info, I have already checked indiedb out, but I didn't hear about gamejolt before, I will check it out.
Actually first phase of our marketing plan comes after we finish our website and demo. Right now we are in phase 0.5 dropping some music and screenshots here on steemit. Once the demo and website are finished we will release the demo and send it to all the game reviewers I can get to. I am compiling the list of reviewers and their contacts and I am currently at above 100.
We will probably publish the list somewhere on our website so I will drop you the link once it is finished in case you need it for your next game.