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.

Execution · Practiced Mastery
An arcade FPS that scores you for killing enemies in the most creative ways possible.

Execution · Practiced Mastery
A co-op wave shooter where squads hold corridors against escalating specimen hordes for cash and headshots.
Bulletstorm leans Execution (Practiced Mastery); Killing Floor leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Bulletstorm
Leash, kick, and shot timing drive skillshot chains
Killing Floor
Headshots on zeds, kiting, weld timing
Bulletstorm leans a little harder on reads, though the gap is small.
Bulletstorm
Enemies are scripted fodder for your combos
Killing Floor
Zeds follow fixed behaviours, never model you
Killing Floor leans a little harder on variance, though the gap is small.
Bulletstorm
Arenas and spawns are fixed and learnable
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.
Bulletstorm
Maximising skillshot score per arena is a solvable puzzle
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.