The Day involves something that hasn't been attempted before on such a grand scale: time travel. Players (even low level ones) will have the ability to jump through time and visit the near future as well as the distant past.
In one example players can travel back to Paris, circa 1806, for the construction of the famous French monument the Arc de Triomphe. However, in this game's alternate reality it's not being built to honor those who fought for France during the Napoleonic Wars... it's camouflage for something more valuable in the war between the game's factions.
Lee says that when you change something in the past -- it will matter. While it might only be a new item or skill, if the mission is big enough (like the one mentioned above) it could literally change a world landmark, which in turn triggers new villains or new settings. "So everyone -- whether they participated or not -- will experience the results."
Very ambitious. The time paradoxes alone boggle the mind! But if Reloaded can pull this off successfully... we think many day's worth of time will end up getting lost.