The North American version of the game's case cover is reversible. Take it out of the case and look at the other side to see an alternate cover

Unlimited Ammo for the Seburo, submachine gun, assault rifle, shotgun, hand grenades, spark grenades, and knives for Single-Player Campaign by Complete the game on Easy Mode
Three additional costumes for Motoko Kusanagi, three additional costumes for Batou, and yellow menus for Single-Player Campaign byComplete the game on Easy Mode
Playable Motoko Kusanagi and Batou, and unlocking Dome Level in Multiplayer Game by Complete the game on Easy Mode
Armed Suit and Think Tank playable in Multiplayer Game by Complete the game on Normal Mode
Three additional paint jobs for Tachikoma for Single-Player Campaign by Complete the game on Hard Mode
Tachikoma playable in Multiplayer Game by Complete the game on Hard Mode
Napalm Launcher for Motoko Kusanagi, Laser Gun for Batou, and unlimited ammo for laser gun and napalm launcher for Single-Player Campaign by Collect all 120 fans in the game
Unlimited ammo for grenade launcher, rocket launcher, missile launcher, sniper rifle, and missile pod by Complete all 12 missions without using a continuing once.

New difficulty settings
Successfully complete a stage on the hard difficulty setting without using the infinite ammunition option or choosing a weapon. If your score penalties were low and your total score high, the very hard difficulty setting will be unlocked. Do the same under that setting to unlock the next difficulty. The order is: very hard, aggressive, dangerous, execution, hopeless, nightmare, and champion.


the difficulty levels:
Very Hard 15,000
Aggressive 22,000
Dangerous 34,000
Execution 50,000
Hopeless 75,000
Nightmare 90,000
Champion 120,000

These fans will appear after beating the game once, there will be 10 fans per mission (some are easy to find and some are not) Shoot at them to collect them.

By destroying all 120 fans you'll get:
Laser gun and Napalm launcher for use in Multiplayer Game.
Napalm Launcher for Motoko Kusanagi, Laser Gun for Batou, and unlimited ammo for laser gun and napalm launcher for Single-Player Campaign.

The best way to obtain the higher level difficulty is to play Mission 8, AT Training Ground, in the highest difficulty you have. Defeat the 3 think-tank and a few armed suits and you'll have more than enough time to destory them. In the more difficult levels, jump on top of those platform and just rain your chain-gun on them, but beware of jumping think-tanks because they can jump to anywhere you can too.

You must complete each 12 levels without using a continue to unlock. Do not confused this with the Continue at the menu screen. When you select Continue on the menu screen, look for an icon on the corner of the screen. When you see it, that means the level has been past without using a continue. There is no specific order of levels needed to be done to unlock.
The prizes of doing this are the following ones:
Unlimited ammo for grenade launcher, rocket launcher, missile launcher, sniper rifle, and missile pod in Single-Player Campaign.