One of the most immersive ways to offer player experiences comes in the form of open puzzles. As a designer, one of the best things you can offer your players is an opportunity to engage in meaningful play, and open puzzles provide an interesting mix of dynamically flexible content and a capacity for hand-crafted outcomes by allowing a number of solutions to a problem based on emergent solutions rather than explicitly pre-determined outcomes.
Take, for example, Scribblenauts, in which many of the puzzles involve selecting a single item or person that will solve a problem. They allow the player to make decisions from a broad pool of possible choices, permitting fluid and flexible play by sparing the player from having to find the one solution to their problem, but also provide a meaningful outcome in the sense that all the possible solutions to a problem will produce a similar outcome.
For instance, a challenge might require a “tool-mechanic”, which means that a number of things, such as a wrench, a drill, or a hammer. These would then be acceptable solutions to the problem. If desired, further qualifications could be added, or even relaxed. I recommend using a class or adjective-driven system for this, rather than trying to manually add options in, as this can accidentally preclude logical choices, though it’s also sometimes detrimental to work based on these methods on account of the potential to create nonsensical choices; a broken car could conceivably be fixed with any of these three tools, but it doesn’t make much sense to have a car with a specific type of damage be fixed by all three. Part of working with open puzzles requires some degree of flexibility, which is typically accomplished by skimping on detail, accepting a certain degree of nonsense answering, or making variable solutions; in some cases the end result may be different in one case than another; this is typically done on a per-puzzle basis.
Before I go back and give examples, I’m going to make a key note; puzzles are not just the things that happen in adventure games when you need to find an item or in riddle segments of a larger RPG. To a certain degree, every element of play is a puzzle; having to figure out the best way to keep the goblins from invading the village again is in and of itself a puzzle, and different outcomes may be worse than others. For instance, it’s possible for players in a truly emergent environment to either destroy the goblins entirely, build a wall around the village, or, if they’re feeling particularly Pyrrhic or evil, just destroy the village. Either way, the goblins trouble the village much less. This last option may only make sense to the quest logic system of the game (elimination of the relationship between the two parties), but it’s a valid option when the puzzle is taken at its most literal and vague wording. In this sense an open puzzle permits several different outcomes to the same event, much like nonlinearity except with the benefit of having the ability to focus into a central path; the Game of Thrones RPG that was otherwise horrible made good use of this, creating several options for the players to change small events through the course of the game without impacting the main plot, but giving them the ability to choose the way they solve their problems.