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
An over-the-top horde shooter throwing hundreds of charging enemies at you.
Bulletstorm leans Execution (Practiced Mastery); Serious Sam: The Second Encounter 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
Serious Sam: The Second Encounter
Circle-strafing huge horde waves tests stamina and aim
Bulletstorm leans a little harder on reads, though the gap is small.
Bulletstorm
Enemies are scripted fodder for your combos
Serious Sam: The Second Encounter
Enemies charge in fixed patterns
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Bulletstorm
Arenas and spawns are fixed and learnable
Serious Sam: The Second Encounter
Wave compositions memorised after one run
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
Serious Sam: The Second Encounter
Prioritising targets and managing arenas is 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.