Or you can buy it from the Humble Store.
There’s also a Supporter’s Edition, which comes with a bunch of fun extras:
- Play through Heat Signature’s development with 8 early prototypes from its 3.5 year development.
- Watch 9 developer commentary videos showing and explaining its evolution: from drilling through hulls to liberating empires. (Total: 70 minutes)
- Own the full soundtrack in 320kbps MP3 format. (19 tracks, 83 minutes)