Gameplay - Fundamentals of Game Design - page 261

Some challenges must include time pressure by the way they are defined—a test of
the player's reaction time, for example. A test of pure reaction time (hit the button
when the light comes on) requires no intrinsic skill at all. The carnival game Whac-
a-Mole is a real-world example.

Stress
If a challenge includes time pressure, a new factor comes into play: stress . Stress
measures how a player perceives the effect of time pressure on his ability to meet a
challenge requiring a given level of intrinsic skill. The shorter the time limit, the
more stressful the situation. Succeeding in a stressful game requires both quick
reflexes and a quick mind. The challenges of Tet r is do not require a great deal of
intrinsic skill—if the player had plenty of time to think about the task, it would be
easy to keep the blocks from piling up—but Tet r is is stressful because the player
must complete the task under time pressure. Golf, on the other hand, demands skill
without being stressful—at least, in the sense of heavy time pressure. It would be
considerably more stressful if the rules imposed more time pressure.

Games often create physical stress on the player's body. Time pressure requires play-
ers to use their eyes and hands more quickly; it makes them stiffen their muscles,
and it raises their heart rates and adrenaline levels. Many people love this sensa-
tion, but you should modulate the pacing of your game to give them time to rest.
Chapter 12 discusses this in more detail in the section “Vary the Pacing.”

Absolute Difficulty
Absolute difficulty refers to intrinsic skill required and stressfulness put together.
When a game offers multiple difficulty levels, the easy mode both demands less
skill and exerts less stress than the hard mode. Some players like a challenge that
demands a lot of skill but they can't tolerate much stress. If they know they have
plenty of time to prepare for a challenge, they're perfectly happy for the challenge
to require great skill. Others thrive on stress but don't have much skill. Simple,
high-speed games like Tet r is and Collapse! suit them best. Figure 9.3 shows a graph
of the relationship of intrinsic skill and stress in various games or tasks. The higher
the task ranks on both scales, the greater its difficulty.

NOTE The absolute
difficulty of a challenge
consists of a combina-
tion of the intrinsic
skill required to meet
the challenge without
time pressure and the
stress added by time
pressure. When you're deciding how difficult you want your game to be, think about both

skill levels and stress, and keep your target audience in mind. Teenagers and young
adults handle stress better than either children or older adults because teenagers
and young adults have the best vision and motor skills. When you allow the player
to set a difficulty level for the game, try to preserve an inverse relationship between
skill level and stress at that particular level of difficulty. If a challenge requires
more skill, give the player longer to perform it, and vice versa.