head to head
Moonlander 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 physics lunar-lander game testing precise thrust and descent control.
Half-Life 2 leans Execution (Pure Mechanics); Moonlander leans Execution (Pure Mechanics).
Moonlander leans clearly harder on execution.
Half-Life 2
Gravity gun and shooting demand precision.
Moonlander
precise thrust control to land safely
Half-Life 2 leans a little harder on reads, though the gap is small.
Half-Life 2
Combine AI scripted, non-adaptive.
Moonlander
no opponent, physics-based challenge
Moonlander leans a little harder on variance, though the gap is small.
Half-Life 2
Almost no randomness.
Moonlander
terrain and fuel randomness minor
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Half-Life 2
Linear progression with no builds.
Moonlander
fuel management and descent strategy
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.