head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, 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
Uncovering a fixed murder mystery through inventory puzzles and deduction.
999: Nine Hours, Nine Persons, Nine Doors leans Optimization (Systems & Chaos); Still Life leans Optimization (Pure Optimization).
Still Life leans a little harder on execution, though the gap is small.
999: Nine Hours, Nine Persons, Nine Doors
Tapping through text and puzzles, zero dexterity
Still Life
Pointing and clicking carries no physical demand
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
Still Life
The killer is a fixed narrative, not an adapting opponent
999: Nine Hours, Nine Persons, Nine Doors leans a little harder on variance, though the gap is small.
999: Nine Hours, Nine Persons, Nine Doors
Hidden story branches and twists drive first playthroughs
Still Life
The mystery's facts are hidden until uncovered
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
999: Nine Hours, Nine Persons, Nine Doors
Escape-room puzzles and route flowchart are fully solvable
Still Life
Inventory puzzles and deduction steps have fixed solutions
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.