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.

Execution · Practiced Mastery
A gritty WWII Call of Duty that introduced the Zombies mode.

Execution · Pure Mechanics
A top-down shooter testing aim and movement against relentless enemy hordes.
Call of Duty: World at War leans Execution (Practiced Mastery); Serious Sam's Bogus Detour leans Execution (Pure Mechanics).
Serious Sam's Bogus Detour leans a little harder on execution, though the gap is small.
Call of Duty: World at War
Twitch gunfights in fast multiplayer lobbies
Serious Sam's Bogus Detour
Top-down aiming and crowd-dodging are the lead
Call of Duty: World at War leans a little harder on reads, though the gap is small.
Call of Duty: World at War
Human opponents reward positioning prediction
Serious Sam's Bogus Detour
Enemy hordes follow scripted rushes, not adaptive
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: World at War
Random lobbies, spawns, and zombie waves
Serious Sam's Bogus Detour
Spawn timing and drops add some chaos
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: World at War
Perk loadouts and map control are learnable
Serious Sam's Bogus Detour
Weapon choice and arena positioning matter underneath
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.