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 · Pure Mechanics
A top-down shooter testing aim and movement against relentless enemy hordes.

Execution · Practiced Mastery
Co-op-focused action sequel hurling Titus against Tyranid swarms with parry-heavy melee combat.
Serious Sam's Bogus Detour leans Execution (Pure Mechanics); Warhammer 40,000: Space Marine 2 leans Execution (Practiced Mastery).
Serious Sam's Bogus Detour leans a little harder on execution, though the gap is small.
Serious Sam's Bogus Detour
Top-down aiming and crowd-dodging are the lead
Warhammer 40,000: Space Marine 2
Parry, dodge and gun-strike timing against swarms
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Serious Sam's Bogus Detour
Enemy hordes follow scripted rushes, not adaptive
Warhammer 40,000: Space Marine 2
PvP Eternal War adds some human prediction
Serious Sam's Bogus Detour leans a little harder on variance, though the gap is small.
Serious Sam's Bogus Detour
Spawn timing and drops add some chaos
Warhammer 40,000: Space Marine 2
Tyranid swarm spawns vary run to run
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Serious Sam's Bogus Detour
Weapon choice and arena positioning matter underneath
Warhammer 40,000: Space Marine 2
Class builds and perk loadouts reward planning
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.