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

Optimization · Pure Optimization
Solvable type-matchup and team-building math across a scripted adventure.
Fallout Shelter leans Optimization (Pure Optimization); Pokémon Alpha Sapphire leans Optimization (Pure Optimization).
Pokémon Alpha Sapphire leans a little harder on execution, though the gap is small.
Fallout Shelter
Tapping menus only
Pokémon Alpha Sapphire
Turn-based menus, zero physical ceiling
Pokémon Alpha Sapphire leans a little harder on reads, though the gap is small.
Fallout Shelter
No opponent
Pokémon Alpha Sapphire
Campaign trainers are scripted; PvP is optional endgame
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
Pokémon Alpha Sapphire
Encounters, abilities and catch rolls add mappable RNG
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
Pokémon Alpha Sapphire
Type math, breeding and team building are the core
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.