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
The console FPS landmark that introduced Master Chief and the ring world.

Execution · Practiced Mastery
Stick execution and opponent prediction inside licensed tournament football.
Halo: Combat Evolved leans Execution (Practiced Mastery); UEFA Champions League 2006–2007 leans Execution (Practiced Mastery).
Halo: Combat Evolved leans a little harder on execution, though the gap is small.
Halo: Combat Evolved
Aim, grenade timing, and vehicle control
UEFA Champions League 2006–2007
Pass timing and shot placement decide most goals
UEFA Champions League 2006–2007 leans a little harder on reads, though the gap is small.
Halo: Combat Evolved
Multiplayer duels reward reading humans
UEFA Champions League 2006–2007
Human opponents bait tackles and disguise attacks
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Halo: Combat Evolved
Covenant AI varies tactics slightly
UEFA Champions League 2006–2007
Deflections and AI bounces add match noise
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Halo: Combat Evolved
Weapon sandbox knowledge and encounter routing
UEFA Champions League 2006–2007
Squad selection and tactical setup are solvable preparation
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.