head to head
Contra: Hard Corps asks more than Half-Life 2, and the gap is execution.

Execution · Pure Mechanics
Memorising brutal scripted patterns and executing them without a single slip.

Execution · Pure Mechanics
Landmark FPS built on physics puzzles and tight gunplay.
Contra: Hard Corps leans Execution (Pure Mechanics); Half-Life 2 leans Execution (Pure Mechanics).
Contra: Hard Corps leans clearly harder on execution.
Contra: Hard Corps
One-hit deaths under relentless bullet pressure demand perfect inputs
Half-Life 2
Gravity gun and shooting demand precision.
Half-Life 2 leans a little harder on reads, though the gap is small.
Contra: Hard Corps
Bosses are fully scripted setpieces
Half-Life 2
Combine AI scripted, non-adaptive.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Contra: Hard Corps
Everything fixed once routes and patterns are known
Half-Life 2
Almost no randomness.
Contra: Hard Corps leans clearly harder on optimization.
Contra: Hard Corps
Memorising boss patterns, weapons and branching routes is mandatory
Half-Life 2
Linear progression with no builds.
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.