The Witness

Hide questions players don't know they can ask. The Witness looks like a grid-panel game until, hours in, a player notices a river that resembles a grid line and realises the whole island is full of puzzles they can draw on.

The reveal makes players wonder what else they missed. Tunic designer Andrew Shouldice describes the effect: "suddenly the entire path that you've traveled becomes littered with question marks."

Make the biggest secrets genuinely easy to miss. Blow designed the environmental puzzles to be optional and missable so finding them felt like a true personal discovery: "it had to be legitimately likely that you could finish the game and never see that stuff."

Like the panels, the hidden puzzles rest on seeing something real that was in front of you all along, which Blow argues makes the epiphany more meaningful than an arbitrary challenge.

A visible end goal keeps players oriented all game. Finishing each puzzle set fires a laser to the top of the mountain, showing one of seven locks opening, so the goal stays clear and in view throughout.

Mark Brown: "The mountain and the lasers are consistently visible."

Optional sound puzzles and a crosshair cover other disabilities. Audio diaries are subtitled and the sound-based puzzles are effectively optional, so deaf and hard of hearing players are mostly not blocked. A crosshair option helps reduce simulation sickness even though the game has no guns.

Click-to-move on PC makes the whole game playable one-handed. The PC version offers a click-to-move scheme alongside mouse and keyboard, so the entire game works with one hand.

Optional sound puzzles and a crosshair cover other disabilities. Audio diaries are subtitled and the sound-based puzzles are effectively optional, so deaf and hard of hearing players are mostly not blocked. A crosshair option helps reduce simulation sickness even though the game has no guns.

An unsolvable door near the start pulls players forward. Early on, players meet a puzzle door they essentially cannot solve yet. It sticks in their head and they keep playing to learn what is behind it.

Mark Brown says he finds the game impossible to put down: "you'll need to know what's behind that door."

The line-drawing rules came from playtesting a mechanic, not a planned puzzle type. While playtesting line drawing on a grid, Blow noticed he was often partitioning the grid's cells, and that observation became a core rule of The Witness.

At IndieCade 2011 Blow said the puzzle type came from "asking these little known questions," not from a top-down demand for a certain kind of puzzle. It came out of a simple process of exploration early in development.

Each puzzle stages one surprising consequence of a rule. Two near-identical panels make the cell-partitioning rule visible: a simple loop solves the first, but in the second the exit has moved and the same loop cuts it off.

Blow uses misdirection so the obvious move fails, which stops players from brute-forcing past the idea, and pairs a simple puzzle with a bigger version nearby so players can compare what the rule changed.

Push every rule through every element of the game. Once he had a rule, Blow asked how each part of The Witness could be twisted by it: the grid, the cells, the line, the environment and the panel itself.

Cut rules that are unsurprising, overlapping or say nothing. Blow edits out mechanics, rules and puzzles that lack surprise, repeat each other or feel contrived. The Witness itself is a spin-off of a shelved game whose core mechanic did not offer enough to explore.

He also keeps things that are not fun if removing them would make the game feel incomplete.

Teach every mechanic early, then only recombine what players know. The Witness introduces its elements upfront with quick introductory puzzles. Harder puzzles change set-ups, combinations and layouts rather than adding new tools, and most explore a single idea.

There are few red herrings or arbitrary steps, so a solved puzzle means "I understand" and feels fair. Once the solution is seen, carrying it out is relatively effortless. Blow: "a puzzle is never just a puzzle. It's a communication of an idea from the designer to the player."

Make the biggest secrets genuinely easy to miss. Blow designed the environmental puzzles to be optional and missable so finding them felt like a true personal discovery: "it had to be legitimately likely that you could finish the game and never see that stuff."

Like the panels, the hidden puzzles rest on seeing something real that was in front of you all along, which Blow argues makes the epiphany more meaningful than an arbitrary challenge.

Braid, Blow's earlier game, found its rules the same way. Coding unlimited rewind showed some objects could be made immune to it, and that rule was then applied to enemies, keys, doors, clouds, platforms and the player character.

Blow dropped Braid's turn-based world because its consequences were not surprising. Braid was also a spin-off of a shelved game.