For those interested in this type of game, the site game giveaway of the day is offering this as a free download for today.
I can't link the url without this post getting an error, but just google game giveaway of the day, and it should be the first link. It is a total legit site, no illegal downloads. They offer free games straight from the developers with their consent, but only for a 24 hour period. Sometimes the game is a HOG, so it is worth checking out every once in a while. I've never had an issue downloading from the website.