Darwinian Difficulty: Designing Games That Make Players 'Adapt Or Die'
Bycer looks at titles like Demon's Souls and Ninja Gaiden Black, which have what he calls Darwinian difficulty: summarized by the phrase "adapt or die." These games start and finish at a consistently high difficulty level and force the player to quickly ramp up to that challenge.
Since such games already start at their maximum difficulty level, they can actually seem to get easier as players develop new skills, lowering the subjective difficulty as they go.
Though games with Darwinian difficulty don't get harder, Bycer stresses that these titles till need to show growth as they progress, through the introduction of new enemies and situations or improved abilities and weaponry.
Yet designers have to be careful that these player upgrades don't overwhelm player skill, which should be the most important determinant of success in this type of game. Bycer suggests health upgrades as a safe way to give the player a buffer without getting in the way of their skill.
Games with Darwinian difficulty should similarly never remove a useful tool from the player's arsenal. Bycer criticizes Bayonetta, which late in the game introduces enemies that are immune to the protagonist's important "Witch Time" dodging ability.
Bycer also points out that having flat, Darwinian difficulty doesn't mean a game can't also have a difficulty selection system. Even an "easy" mode in a game like Ninja Gaiden Black is more difficult than most normal games, he points out, but still gives players a chance to "pump up" for higher difficulties.
The full feature goes into much more detail on the ways in which Ninja Gaiden Black and Demon's Souls manage to tread the fine line of being consistently difficult while still satisfyingly beatable with dedication and skill.