head to head
Shock Troopers: 2nd Squad 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 top-down run-and-gun about aiming and dodging through scripted battlefields.
Half-Life 2 leans Execution (Pure Mechanics); Shock Troopers: 2nd Squad leans Execution (Pure Mechanics).
Shock Troopers: 2nd Squad leans clearly harder on execution.
Half-Life 2
Gravity gun and shooting demand precision.
Shock Troopers: 2nd Squad
Aiming, dodging, and movement decide top-down combat
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life 2
Combine AI scripted, non-adaptive.
Shock Troopers: 2nd Squad
Enemies follow fixed scripted patterns
Shock Troopers: 2nd Squad leans clearly harder on variance.
Half-Life 2
Almost no randomness.
Shock Troopers: 2nd Squad
Enemy spawn placement adds momentary surprise
Shock Troopers: 2nd Squad leans a little harder on optimization, though the gap is small.
Half-Life 2
Linear progression with no builds.
Shock Troopers: 2nd Squad
Weapon use and route memorization reward 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.