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 · Competitive PvP
Large-battle aim and positioning with light prediction against human players.

Execution · Pure Mechanics
A fast arcade FPS whose skill test is twitch aim plus couch-rival prediction.
Star Wars: Battlefront II leans Execution (Competitive PvP); TimeSplitters leans Execution (Pure Mechanics).
TimeSplitters leans a little harder on execution, though the gap is small.
Star Wars: Battlefront II
Aimbot dominates infantry fights and starfighter dogfights
TimeSplitters
Fast arcade gunplay rewards twitch aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Star Wars: Battlefront II
Human opponents in multiplayer create modest prediction play
TimeSplitters
Local multiplayer adds human guessing; bots do not adapt
Star Wars: Battlefront II leans a little harder on variance, though the gap is small.
Star Wars: Battlefront II
Spawns, vehicle availability and hero pickups add chaos
TimeSplitters
Spawn and pickup timing add mild uncertainty
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Star Wars: Battlefront II
Class choice and map control reward learned plans
TimeSplitters
Challenge times and map control are learnable
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.