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

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

Optimization · Pure Optimization
Tactical mecha RPG where customizing wanzer parts and link systems outweighs battlefield improvisation.
Fallout Shelter leans Optimization (Pure Optimization); Front Mission 4 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
Front Mission 4
Menu-driven turn-based combat
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
Front Mission 4
Fixed mission AI with set behaviors
Fallout Shelter leans a little harder on variance, though the gap is small.
Fallout Shelter
Incident spawns and lunchbox loot rolls
Front Mission 4
Accuracy rolls and link-attack triggers
Front Mission 4 leans a little harder on optimization, though the gap is small.
Fallout Shelter
Dweller stats and room layout are fully solvable
Front Mission 4
Wanzer part builds and pilot skill loadouts are the game
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.