Outcast was one of those games that was so amazing most people never even got to play it. It just...shone too damn brightly. So much so that this 2010 remake of a 1999 game may well get more exposure.
Open Outcast is a fan-made mod for Crysis Wars, which seeks to recreate Appeal's brilliant open world adventure title with visuals a little more appropriate for this third millennium. Not that Outcast's graphics were bad - indeed, for 1999 they were revolutionary - it's just, running on Crysis' engine, it now looks better.
All you need to download the mod is a trial version of Crysis Wars. After that, you can grab a demo of Open Outcast from the mod's official site. If you've never played the original, I'd highly recommend it.