Soldier of Fortune Additional Payback is intended to fix, polish, and expand upon the original Soldier of Fortune Payback game. The main features are the reworking of the weapons and the addition of alternate versions of the levels.
Since the "ACR-2" is available like any other gun in the mod, it left an opening in the game for a new secret weapon. The M2HB machine gun has taken the role as the game's secret unlock-able weapon.
To access it, just perform the same unlocking sequence used to unlock the "ACR-2" in Soldier of Fortune Payback:
From the main menu, select “single player”. Next, select “start new game”. Next, type the following keys on your keyboard's arrow keys: up, up, down, left, right, right, down. It can be tricky to get the speed just right. When entered correctly a confirmation box appears. You can now select the weapon in either campaign or mission select modes. The video shows backing out of the campaign and switching over to “mission select”.
Note that while the game does present you with a difficulty select menu in “mission select” mode, the cheat code will only work when done at the difficulty select menu of “start new game”. The M2HB will remain available for selection until the game is closed.
What do we have to do to unlock the M2HB?! Please respond.