head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

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

Execution · Practiced Mastery
Arcade flight and shooting precision over fixed missions with learnable score routes.
Half-Life 2 leans Execution (Pure Mechanics); Star Fox: Assault leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life 2
Gravity gun and shooting demand precision.
Star Fox: Assault
Arwing dogfights and on-foot aim demand steady twitch play
Star Fox: Assault leans a little harder on reads, though the gap is small.
Half-Life 2
Combine AI scripted, non-adaptive.
Star Fox: Assault
Versus mode adds light human prediction; campaign is scripted
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.
Star Fox: Assault
Missions play out identically each run
Star Fox: Assault leans a little harder on optimization, though the gap is small.
Half-Life 2
Linear progression with no builds.
Star Fox: Assault
Scoring routes and boss patterns are learnable
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.