FUNDAMENTALS OF GAME DESIGN, SECOND EDITION

Depth Versus Breadth

The more options you offer the player at one time, the more you risk scaring off a player who finds complex user interfaces intimidating. A UI that provides a large number of options simultaneously is said to be a broad interface. If you offer only a few options at a time and require the player to make several selections in a row to get to the one he wants, the user interface is said to be deep.

Broad interfaces permit the player to search the whole interface by looking for what he wants, but finding the one item of current interest in that broad array takes time. Once the player learns where to find the buttons or dials, he can usually find them again quickly. Players who invest the (sometimes considerable) training time find using a broad interface to be efficient; they can quickly issue the commands they want. The cockpit of a commercial passenger aircraft qualifies as an enor­mously broad interface; with such a huge array of instruments, the pilot can place his hand on any button he needs almost instantly, which makes flying safer. On the other hand, pilots must train for years to learn them all.

Deep interfaces normally offer all their choices through a hierarchical series of menus or dialog boxes. The user can quickly see what each menu offers. He can't
know in advance what sequence of menu choices he must make to find the option he wants, so the menus must be named and organized coherently to guide him. Even once he learns to find a particular option, he still has to go through the sequence of menus to get to it each time. On the other hand, using a well-designed deep interface takes almost no training.

It's a good idea to offer both a deep and a broad interface at the same time: deep for the new players, broad for the experienced ones. You can do this on the PC by assigning shortcut keys to frequently used functions. The large number of keys on a PC keyboard enables you to construct a broad interface easily. Console machines, with fewer controller buttons available and no mouse for pointing to screen ele­ments, offer fewer options for creating broad interfaces.

If you can only offer one interface, try to make the breadth and depth of your inter­face roughly equal; but avoid making anything more than three or four levels deep if you can help it. When deciding how to structure menus, categorize the options by frequency of access. The most frequently accessed elements should be one or two steps away from the player at most. The least frequently accessed elements can be farther down the hierarchy.