When you access this Easter egg normally in the game, you can only play the first two levels. Dataminers determined that the entire game was actually shipped with Homefront, with no obvious way to access it. Now we have actual confirmation that the full game with multiplayer is indeed playable, if you know the correct code.

Now that there's renewed interest, hopefully it shouldn't take long before somebody discovers the correct code and patches the Homefront executable to jump straight into TimeSplitters 2.