head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Pure Optimization
A vault management sim about optimising dwellers, rooms, and resource loops.

Optimization · Pure Optimization
A mystery visual novel testing deductive matching of evidence to scripted contradictions.
Fallout Shelter leans Optimization (Pure Optimization); 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.
Fallout Shelter
Tapping menus only
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.
Fallout Shelter
No opponent
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.
Fallout Shelter
Incident spawns and lunchbox loot rolls
Gyakuten Kenji 2
Case truths are hidden information revealed on rails
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout Shelter
Dweller stats and room layout 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.