The home computer version of The Goonies had an interesting puzzle on the first screen. Mama Fratelli blocked the exit, and would 'kill' the player on contact. You had to operate a money printing printing press to fire money out of the window, making her run outside to catch the notes. As the money fluttered down you had enough time to run to the exit.
'Gates' are often present in games. They act as an obstacle to progress through the game, or otherwise gain items, content and information. They may kill the player character or act like a brick-wall, but they usually act as something to be overcome with objects found elsewhere in the game or level.
Non-player characters (NPCs) often act as 'people-gates' in games. In most cases they will reward you by removing a block to a passage, or simply by granting you a significant item or money. They offer more interesting solutions than objects, and you can use their dialogue or character to figure out the solution.
Many of the methods can be distilled to a few techniques. Let me know if you think of any others:"Give me a specific item, and I'll let you pass / give you another item"
The simplest form of fetch-quest, and a fairly robust and compelling means to flow through a lot of games. Still commonplace, and a pretty good way to make a door with a key more interesting."Tell me why I should let you pass / give you an item"
Presenting a character with information can often persuade them to let you pass. Sometimes an item will be used to represent information, such as a photograph or letter. Misinformation is just as good."Give me 50 wolf pelts / Give me $100!"
The simplest gates will request a number of items before allowing passage, or presenting you with a new item. After satisfying this need, they may present a new request for money or trinkets.Dispatch the Blaggard!
Kill them, put them to sleep, or tie them up. Sometimes the only option is to take them out of commission.Use a disguise!
An oldie but a goodie. Grab a lab-coat, fake moustache, or complete a number of quests in order to crossdress your way to victory in Final Fantasy VII! Holding up a bush to use as a sneaking item is also a good disguise. Create a Diversion
If you can remove the person for a period of time, you can gain safe passage, as shown in the Goonies example above. Alternatively a diversion may allow you to steal the item you need to attain, such as snatching a key behind a guard.Use a third party to detain or overcome them.
Sometimes the only way to get past a person is to enlist another character, or perhaps creature, to take them out of the picture. Hire some prostitutes to distract a guard, or let a billy-goat kick the troll from the bridge.
There's also the larger discussion of charming, intimidating or befriending. This is often a series of interest items, information items and money, or a complex series of conversation options that operate in a maze-like fashion. Alternatively conversation will rely on stats, which is just a form of the information objecct as listed above.
Are there any particularly creative examples of passing NPCs in games that you can think of?