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

Optimization · Mind & Math
Console-first RTS translating Halo's factions into streamlined base-and-army battles.

Optimization · Pure Optimization
A survival strategy game about building a civilization while battling other players.
Halo Wars leans Optimization (Mind & Math); War Selection 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.
Halo Wars
Controller macro is deliberately light
War Selection
Some real-time control but not twitch-focused.
Halo Wars leans a little harder on reads, though the gap is small.
Halo Wars
Versus humans, build choices are mindgames
War Selection
Human opponents in multiplayer require some prediction.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Halo Wars
Scouting hides enemy composition early
War Selection
Resource spawns and combat rolls add unpredictability.
War Selection leans a little harder on optimization, though the gap is small.
Halo Wars
Build orders and counter-unit economy
War Selection
Base-building and civilization strategy are deeply solvable.
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.