WorthPlaying writes: "Phantom EFX's Darkest of Days, using 8Monkey Labs' proprietary Marmoset game engine, is a story-rich, first-person shooter presenting an intriguing story of time-travel to some of the darkest periods in the history of mankind. Check out the 740mb demo to try out a game that mixes Roman gladiators with machine guns, civil war era with heavily armored special agents ..."