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
Strategic dismemberment under resource pressure, solved by upgrade planning and practiced limb-aiming.

Execution · Practiced Mastery
The PS1 third-person espionage shooter following agent Gabe Logan against a viral terror plot.
Dead Space (2008) leans Execution (Practiced Mastery); Syphon Filter leans Execution (Practiced Mastery).
Dead Space (2008) leans a little harder on execution, though the gap is small.
Dead Space (2008)
Precise limb-targeting under Necromorph pressure is the core skill
Syphon Filter
Taser duels and headshots under pressure test the hands
Dead Space (2008) leans a little harder on reads, though the gap is small.
Dead Space (2008)
Necromorphs follow fixed approach patterns, not player modelling
Syphon Filter
Terrorist AI is scripted spawns and patterns
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dead Space (2008)
Store stock is deterministic; minor drop variance on kills
Syphon Filter
Minor first-run uncertainty in enemy placements
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Dead Space (2008)
Weapon upgrading, power-node routing and stasis timing are optimisable
Syphon Filter
Memorizing levels and weapon stashes makes runs routine
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.