Hexic HD came pre-installed on most Xbox's back in the day but many went and deleted it looking for more space on their Hard Drive only to find when searching for it on the marketplace it was not on there…
Well now it is free for everyone, if you never had it get it, if you deleted it get it back.
thanks mate, thats exactly what I did…accidently deleted it :).
and just so everyone knows, you dont actually have to physically download the game now on the xbox, just sign in and add to your download queue for later on. Once 'purchased' its available to download whenever you like for the future.