You'll need to pop your email address into the field at the top of the page, then sign up to the Indie Gala team group before being able to snag your copy. It usually costs £3.99 on Steam.
I slammed this ambitious yet lacklustre shooter in our Super Killer Hornet Resurrection review, but the price was one of my biggest bugbears. For free, I can forgive some of its rougher edges, especially as it reminds me of the good ol' Amiga days in good ways and bad. The British rock hiphop soundtrack from The Sixtyfours is also excellent. UPDATE: Thanks jaystan, who found this long before I did!