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

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

Execution · Pure Mechanics
Browser-era refinement of Quake III, the benchmark for raw arena FPS skill.
Half-Life 2 leans Execution (Pure Mechanics); Quake Live leans Execution (Pure Mechanics).
Quake Live leans clearly harder on execution.
Half-Life 2
Gravity gun and shooting demand precision.
Quake Live
Rail aim and strafe-jump movement are the purest hand test
Quake Live leans clearly harder on reads.
Half-Life 2
Combine AI scripted, non-adaptive.
Quake Live
Duels are mind games against an adapting human opponent
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life 2
Almost no randomness.
Quake Live
Symmetric arenas, full information, almost no randomness
Quake Live leans clearly harder on optimization.
Half-Life 2
Linear progression with no builds.
Quake Live
Item timing and map control are deeply solvable
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.