You raise a very good point. In order to have an adventure game with a lot of objects and “sidequests”, you’d have to give up some puzzles, even good ones, because they wouldn’t work anymore. Puzzles like “sell the bottle because it’s the only way to have a nickel” or “use the electric fence because there is no battery charger in the world”. These kind of puzzles exploit the fact that there are no “substitutes” for some objects. But in a big world there would be substitutes. However, you can have sections of the game where you are not in an open world (say locked up in a dungeon, or on Mars like in Zak), and put these puzzles back. Or you can create objects without substitutes in the whole world (say, a magic amulet). But in general, it’s true that this change does not come for free, and that the puzzle style must be different. I had started saying something similar, when I said that the challenge must now come from the quantity of objects, not from using objects in a way they are not designed to (McGyver style).