No, Non, Not!
'No door can Not be opened with a Non-black key' is a rule-modifying 2D action puzzle game in which the protagonist, who has the power to manipulate the word ‘Nai(no/non/not)’, adventures through a world created by rule sentences.
Summoned by a goddess, the protagonist is given the ability to manipulate negation and must solve a number of stages in order to rescue the princess.
The protagonist can use the given ability to retrieve the negative word ‘Nai’ from a rule statement and then add it to other rule statements.
Contents (Demo version)
8 stages + α
3 endings in total