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
Sprawling action horror with four campaigns and a surprisingly deep combat system.
Halo: Combat Evolved Anniversary leans Execution (Practiced Mastery); Resident Evil 6 leans Execution (Practiced Mastery).
Halo: Combat Evolved Anniversary leans a little harder on execution, though the gap is small.
Halo: Combat Evolved Anniversary
aim and grenade timing carry combat
Resident Evil 6
Deep melee-and-gunplay movement system rewards mechanics
Halo: Combat Evolved Anniversary leans a little harder on reads, though the gap is small.
Halo: Combat Evolved Anniversary
covenant AI is scripted, not adaptive
Resident Evil 6
Agent Hunt PvP adds a sliver of 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
Resident Evil 6
Set-piece campaigns are fixed after first sight
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Halo: Combat Evolved Anniversary
weapon sandbox and routes are solvable
Resident Evil 6
Skill builds and Mercenaries combos 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.