How To Unlock: Finish the game on Hard difficulty.
The trophies for the different difficulty levels stack in this game. Because of this, it is recommended to go straight into Hard to get them all in one playthrough. It’s not that difficult, and will save a lot of time. The single player campaign can be easily beaten in around 6 or 7 hours. After finishing the game on Hard difficulty, you will receive Act IV, Rookie, Captain and General all at the same time. Certain sections may prove to be difficult, but in general it’s easy going enough. Here are some tips on beating the game on Hard difficulty:
■DO NOT RUN – Walk and crawl. Take your time. This is not the game to go Running and Gunning in. It only takes a few shots to put you down, and the AI can shoot pretty well. Divide the levels into small areas, and clear each area as you go.
■KEEP YOUR HEAD DOWN – Your default stance should be crouched. The AI can spot you from miles away, so keep your head down. Crawl when necessary, and stick to cover.
■ONLY KILL ENEMIES IN YOUR WAY – Enemies often have sightlines to each other. So killing a random guy in the distance may alert 5 more that you are there.
■STAY HEALTHY - Heal yourself immediately after being shot by an enemy.
■ALLOW FOR GRAVITY - Bullets drop over distance. This isn't Call of Duty! Aim above your target is far away to hit it correctly.
■HEADSHOTS – Silence is your friend. And an enemy who is shot in the head is not going to set off any type of warning. The sure fire suppression method.
■WATCH THE BAR – Always keep one eye on the status bar. But moving slowly and watching the bar, you can use it to judge the quality of your cover. White is good, red is bad and an empty bar is best.