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
Landmark scripted FPS following Gordon Freeman through the Black Mesa disaster.

Execution · Practiced Mastery
A co-op wave shooter where squads hold corridors against escalating specimen hordes for cash and headshots.
Half-Life leans Execution (Practiced Mastery); Killing Floor leans Execution (Practiced Mastery).
Killing Floor leans a little harder on execution, though the gap is small.
Half-Life
Combat aim and infamous platforming sections
Killing Floor
Headshots on zeds, kiting, weld timing
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life
Marines flank by script, not by modelling you
Killing Floor
Zeds follow fixed behaviours, never model you
Killing Floor leans a little harder on variance, though the gap is small.
Half-Life
Set pieces surprise only on first run
Killing Floor
Spawn waves randomise but quickly become familiar
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life
Resource routing and encounter knowledge for speedruns
Killing Floor
Perk levelling, holdout spots, dosh economy 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.