head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, and it is a single point.

Optimization · Systems & Chaos
A visual novel thriller mixing escape-room puzzles with branching life-or-death story routes.

Optimization · Pure Optimization
A mystery visual novel testing deductive matching of evidence to scripted contradictions.
999: Nine Hours, Nine Persons, Nine Doors leans Optimization (Systems & Chaos); Gyakuten Kenji 2 leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
999: Nine Hours, Nine Persons, Nine Doors
Tapping through text and puzzles, zero dexterity
Gyakuten Kenji 2
Reading text and presenting evidence has no motor test
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
999: Nine Hours, Nine Persons, Nine Doors
Characters follow a fixed script, never adapt
Gyakuten Kenji 2
Witnesses are scripted contradictions, not adapting minds
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
999: Nine Hours, Nine Persons, Nine Doors
Hidden story branches and twists drive first playthroughs
Gyakuten Kenji 2
Case truths are hidden information revealed on rails
Gyakuten Kenji 2 leans a little harder on optimization, though the gap is small.
999: Nine Hours, Nine Persons, Nine Doors
Escape-room puzzles and route flowchart are fully solvable
Gyakuten Kenji 2
Matching evidence to testimony is a fixed logic puzzle
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.