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
Tests raw aim and movement speed in fast classic arena deathmatch.

Execution · Pure Mechanics
Console shooter execution across scripted set pieces and once-massive human multiplayer.
Half-Life Deathmatch: Source leans Execution (Pure Mechanics); Resistance 2 leans Execution (Pure Mechanics).
Half-Life Deathmatch: Source leans a little harder on execution, though the gap is small.
Half-Life Deathmatch: Source
Aim, bunny-hopping and snap reactions decide duels
Resistance 2
Weapon handling and boss dodging demand console-shooter precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life Deathmatch: Source
Predicting human movement and spawn timing matters
Resistance 2
60-player multiplayer rewarded reading humans; campaign Chimera don't adapt
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life Deathmatch: Source
Fixed maps and item timers, little randomness
Resistance 2
Campaign encounters are set pieces
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life Deathmatch: Source
Weapon spawns and map control are learnable systems
Resistance 2
Exotic weapon choice and class co-op roles add planning
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.