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A number of features in the original game were "hidden" as unlockable extras. The game's difficulty level tended to make these extras somewhat difficult to attain, although the means of unlocking them are displayed as part of the end mission brief in each case. It is also possible to download and use custom game profiles which have all the extras already unlocked.

Notable unlockable extras include :

• Supergore mode, over 10x the amount of blood (or acid) emitted from wounds
• Pigsticker mode, the Predator's speargun fires 10x as many bolts per shot
• John Woo mode, the game dynamically slows down depending how much activity is taking place
• Sniper munch mode, giving the Alien the ability to perform the jaw attack from any distance.