SiN/Freeport City Bank

Blade is dropped off by helicopter to one of two places - either through the roof, or on the street. The roof is ideal as it is closer to the key, but there's nothing wrong with the street entrance either.

There is also a secondary objective to rescue hostages. Talk to at least four of them to complete the secondary objective. You may need to rescue more on higher difficulty levels, and they're generally on the main route for completing the level.

Security room key
You first need to find the security room key. First, look for the room with two escalators - this is the direct path from the rooftop entrance, while the ground entrance either requires following the outdoor path or fighting through the main bank lobby.

At the top of the escalators, open the door to the right, and continue to the second set of doors. This leads to a small office, where the key is on the middle desk next to some folder. When you approach the key (or rescue the hostage), there will be additional thugs that drop from the ceiling and attack.

Enemies will reinforce in the office, in addition to the two rooms outside.

Opening the vault
Head to the main lobby, recognized by the fountain. From the escalator room, it can be reached on the second floor, by taking the tunnel that connects directly to this lobby.

Mancini will lower the bandit shield, and flee. When the bandit shield raises, jump over the counter, and exit to the left.

Look for a double door to the left - you can open the door with the key, and enter. To enter the security room, shoot the window and climb through.

The security console is on the right. Disable the security system, and unlock the security doors. You can check the vault combination, which changes each time you play the level.

Enter the combination in the vault, and open the door. Mancini will jump through the hole and escape.

Other items
You can find other items, which aren't critical to the game but lead to several easter eggs.
 * A quarter may be found in the fountain, where you first see Mancini. This is used for a payphone found in one of the lobbies.
 * From the security console, you can get a list of account numbers and PINs, and enter them on the ATM. One of them is for Alexis Sinclair, where you can wire funds to yourself.
 * You can open the teller drawer, and steal some money.