Difficulty and flow
Keep challenge rising with skill so players stay between boredom and frustration, using a sawtooth curve.
Flow
A state of deep absorption where you lose track of time, described by psychologist Mihaly Csikszentmihalyi in his book Flow. It tends to happen when the challenge matches your skill. Too hard for your skill and you feel anxious or frustrated; too easy and you get bored. The band in between is often called the flow channel.
A Tetris player at the right speed for them: every piece needs a quick decision, and they can just about keep up.
challenge
^
| ANXIETY /
| (too hard) / FLOW
| / channel /
| / /
| / / BOREDOM
| / / (too easy)
+------------------------------------> skillAs skill grows (right), the challenge has to grow (up)
to keep the player inside the band.A player is a dot on this chart. Every time they get better, the dot moves right. If the game doesn't push it up as well, it slides down into boredom.
Check yourself
Sina yawns his way through level 3: he clears it first try without really paying attention. Where is he on the flow chart?
- Above the channel: anxious, the level is too hard
- Inside the flow channel
- Below the channel: bored, the level is too easy for his skill
- Off the chart: he isn't playing at all
Show the answer
Below the channel: bored, the level is too easy for his skill
Yes. His skill is well above what the level asks for, so he's in the boredom zone. The game needs to raise the challenge for him.
THE DIFFICULTY CURVE
Rise, dip, rise higher
Skill grows while you play, so challenge has to grow too. A flat difficulty gets boring; a steep one loses people. Most good games use a sawtooth curve: difficulty rises through a stage, drops a little at the start of the next one (often when a new idea is introduced), then climbs again. Overall, it trends upward. A moment of rest after tension makes the next climb feel good.
Tetris keeps it simple and visible: the level number goes up and the pieces fall faster. The player's skill has to keep up.
difficulty
^
| /
| /
| /| /
| / | /
| /| / |/
| / | /
| /| / |/
| / | /
| / |/
| /
| /
+------------------------------> timeEach stage climbs, the next one starts a little lower
than the last peak, and the whole line trends upward.The dip is where a new mechanic usually arrives: easier surroundings while the player learns the new thing.
Check yourself
Which description matches a sawtooth difficulty curve?
- Difficulty stays exactly the same from start to finish
- Difficulty rises within a stage, dips a little when the next stage starts, and trends upward overall
- Difficulty jumps to its maximum in the first level and stays there
- Difficulty goes down steadily so the ending is the easiest part
Show the answer
Difficulty rises within a stage, dips a little when the next stage starts, and trends upward overall
Right. Climb, small dip, climb higher. The dips give rest and room to learn; the overall rise keeps pace with the player's growing skill.
Difficulty knobs you can turn
- Speed: pieces fall faster, enemies move quicker.
- Number or strength of enemies.
- Timing windows: less time to react or jump.
- Resources: fewer health pickups, less ammo, less money.
- Combining two challenges the player already knows.
- Checkpoints: fewer of them means more to replay after a mistake.
Check yourself
Which changes make a level harder without adding new content?
- Enemies move faster
- Fewer checkpoints
- A shorter window to jump between platforms
- The sky changes from blue to orange
- A new music track plays
- Fewer health pickups along the way
Show the answer
Raises the difficulty: Enemies move faster, Fewer checkpoints, A shorter window to jump between platforms, Fewer health pickups along the way
Doesn't change the challenge: The sky changes from blue to orange, A new music track plays
Two ways to fit many players
The player chooses
Difficulty modes (easy, normal, hard) and optional harder goals: collectibles, time trials, a no-damage run. Beginners can finish; experts set their own bar.
The game adjusts
Dynamic difficulty adjustment: the game quietly tunes itself to how well you're doing. Keep it subtle; players tend to dislike noticing that the game is going easy on them, or punishing them for playing well.
Check yourself
Dynamic difficulty works best when players can clearly see the game making things easier for them.
Show the answer
False
False. It usually works best when it's subtle. Many players feel cheated if they notice the game going easy on them, or feel punished if it gets harder just because they're doing well.
FAILING WELL
Make failure fast and fair
A hard game can still feel good if failing is fast (you're back in action in a moment) and fair (you can see why you failed). Long reloads and deaths from nowhere are what really drive players away.
Celeste (2018) is a very demanding platformer, yet many beginners finish it. You respawn almost instantly at the start of the screen, and an optional assist mode lets players slow the game down or make themselves invincible.
Check yourself
Why do game designers so often make their games too hard?
- They want players to fail and quit
- They've played it the most and are its most skilled player
- Hard games are cheaper to make
- Players always ask for harder games
Show the answer
They've played it the most and are its most skilled player
Yes. Hundreds of hours of practice make the designer the best player the game will ever have, so what feels "medium" to them is hard for a newcomer.
Lesson recap
- Flow (Csikszentmihalyi, 1990) happens when challenge matches skill: too hard brings anxiety, too easy brings boredom.
- Skill grows as you play, so challenge has to grow too.
- A sawtooth curve climbs within a stage, dips at the next, and trends upward overall.
- Turn the knobs: speed, enemies, timing, resources, combinations, checkpoints. Offer modes and optional goals.
- Dynamic difficulty (like Mario Kart's item boxes) works best when subtle; make failure fast and fair, as Celeste does.
- Notebook: think of a game that once made you quit, and write whether it was boredom or frustration.