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 · Pure Mechanics
The sequel that built console online multiplayer around ranked Battle Rifle duels.

Execution · Pure Mechanics
A fast arena shooter where raw aim and movement meet item-control strategy.
Halo 2 leans Execution (Pure Mechanics); Unreal Tournament 2004 leans Execution (Pure Mechanics).
Unreal Tournament 2004 leans a little harder on execution, though the gap is small.
Halo 2
BR precision and movement tricks online
Unreal Tournament 2004
Aimbot plus perfect dodging trivializes arena duels
Unreal Tournament 2004 leans a little harder on reads, though the gap is small.
Halo 2
Ranked duels hinge on outplaying humans
Unreal Tournament 2004
Predicting human movement and timing in duels matters
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Halo 2
Matchmaking opponents and spawns vary
Unreal Tournament 2004
Spawns and item timers are knowable, little hidden
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Halo 2
Map control, timers, and weapon spawns
Unreal Tournament 2004
Item timing, map control, and weapon economy are studied
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.