rtcvb32: Though i was talking more from a technical standpoint, not a narrative one. Watching and listening to my GF play book of unwritten tales was hilarious, it was far more the comedy than the story. Can't say most of the puzzled seemed that hard.
It all depends on the quality of the production.
If you just create one "I can't do that" generic response to everything that isn't the correct answer, that is relatively easy. Some adventure engines, like Visionaire, even offer some nearly automatic ways to do that.
But if you create something like Time, Gentlemen, Please, where almost every attempt to combine any possible items provides a unique response, that's an enormous task.
It's also possible to create very challenging puzzles, if that's needed. Some adventure games have invented languages or calculation systems, so you need to figure out the logic behind them in order to solve the puzzles.
rtcvb32: But do puzzles have to keep getting harder? Creative to a degree maybe but not harder. You would want them just challenging enough that they aren't boring you, but not so hard you need a walkthrough. Difficult keys to doors in opposite locations of things just to pad out the time to run into enemies for example is just annoying.
Obviously they don't need to. But most games, regardless of genre, become harder when you play them further. It would also be a bit strange if the game has the biggest challenge first, and after that it becomes easier. The story would need to be something very engaging to keep the players motivated.
In adventure games the first puzzles are usually something like using some item that is already in the inventory, then soon after you need to find items to pick up to add to the inventory, then create new items by combining something in the inventory, and so on.
In action games there is usually some kind of boss fights in the end, it would be a bigger surprise if there weren't any.