RUMOR has it that Alex Garland’s treatment of the Halo subject has been leaked onto the internet, via BitTorrent in a PDF format. At least this is the case made by 1Up. They claim that the script itself, found via one of their forum members, shows a number of parallels with the Latino Script review from December 2005 (back when the movie was in development).
1Up have pasted some pages from the script showing the introduction and intended finale and setup for a sequel. Warning, SPOILERS herein.
This version has since been abandoned, production instead opting for a rewrite by D.B.Weiss.