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
A sci-fi shooter where aim and weapon-switching against scripted alien enemies is the core test.

Execution · Practiced Mastery
Simulation driving precision underpinned by setup tuning and race strategy.
Halo: Combat Evolved Anniversary leans Execution (Practiced Mastery); Project CARS leans Execution (Practiced Mastery).
Project CARS leans a little harder on execution, though the gap is small.
Halo: Combat Evolved Anniversary
aim and grenade timing carry combat
Project CARS
Braking points and wheel control at the sim limit
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Halo: Combat Evolved Anniversary
covenant AI is scripted, not adaptive
Project CARS
Online racecraft against humans adds light positional prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Halo: Combat Evolved Anniversary
enemy spawns and drops vary
Project CARS
Dynamic weather injects some session randomness
Project CARS leans a little harder on optimization, though the gap is small.
Halo: Combat Evolved Anniversary
weapon sandbox and routes are solvable
Project CARS
Setup tuning and pit strategy reward deep study
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.