Alternatively if you are okay with the money going to charity rather than the devs and you even slightly want any of the other games then the GOG promo of three games in return for $5 donation (or 4 for $6.67 and so on) seems a better deal.

http://www.gog.com/news/charity_promo_pick_3_games_donate_5_or_more_100_goes_to_charity