head to head
Quake II asks more than Half-Life 2, and the gap is execution.

Execution · Pure Mechanics
Landmark FPS built on physics puzzles and tight gunplay.

Execution · Pure Mechanics
A methodical shooter that rewards learning enemy layouts and conserving resources across connected military bases.
Half-Life 2 leans Execution (Pure Mechanics); Quake II leans Execution (Pure Mechanics).
Quake II leans clearly harder on execution.
Half-Life 2
Gravity gun and shooting demand precision.
Quake II
Fast strafe-aim against hard-hitting enemies demands clean inputs
Half-Life 2 leans a little harder on reads, though the gap is small.
Half-Life 2
Combine AI scripted, non-adaptive.
Quake II
All enemies are scripted; no adaptive AI present
Quake II leans clearly harder on variance.
Half-Life 2
Almost no randomness.
Quake II
Item and enemy placement is fixed but unknown on first play
Quake II leans clearly harder on optimization.
Half-Life 2
Linear progression with no builds.
Quake II
Ammo and health economy tightly constrains routing through every level
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.