They could go a couple different routes with this and it'd be okay.
Voiceovers with Hayter, James Earl Jones to Vader style.
They could do the whole Beowulf thing to make the movie look game-like and edit Hayter to make him look a little closer.
Christian Bale'd probably have to end up at the top of my list, though. He's probably not the best in the world for the role, but I don't keep up with every indie and underground film to have seen anyone near good enough other than him.
Russel would have been great if this was 15 years ago. MGS Snake/Big Boss was basically a straight rip of him with a bandanna stuck on for good measure, but I don't think he can pull off 30something without digital help.