Head over to Alawars site to get Crusaders of Space for free. What's the catch? You need to download the Alawar game box:
I've been using it since the Beta was first released and have found it to be unobtrusive and if you downloaded any of the Alawa games from the game giveaway site. very useful because you can access all of them from the game box easily. You can also download all of Alawars demos from the game box if you wish.
There's a button that takes you to the free game of the month. This month it's Crusaders of Space (the first one) Granted, it's not as good as Jet's and Guns, but it's still very playable, especially if you're into space shoot Em up's and even more so because it's free.