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

Execution · Pure Mechanics
A skating/grinding platformer emphasizing precise momentum-based movement.

Execution · Pure Mechanics
Landmark FPS built on physics puzzles and tight gunplay.
Aftergrinder leans Execution (Pure Mechanics); Half-Life 2 leans Execution (Pure Mechanics).
Aftergrinder leans clearly harder on execution.
Aftergrinder
precise grinding and platforming skill
Half-Life 2
Gravity gun and shooting demand precision.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Aftergrinder
no adaptive opponent
Half-Life 2
Combine AI scripted, non-adaptive.
Aftergrinder leans a little harder on variance, though the gap is small.
Aftergrinder
minor level randomness
Half-Life 2
Almost no randomness.
Aftergrinder leans clearly harder on optimization.
Aftergrinder
route/combo optimization for scoring
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.