head to head
Nyan Cat: Lost In Space asks more than Half-Life 2, and the gap is variance.

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

Execution · Pure Mechanics
An endless arcade runner testing reflexes against scrolling hazards.
Half-Life 2 leans Execution (Pure Mechanics); Nyan Cat: Lost In Space leans Execution (Pure Mechanics).
Nyan Cat: Lost In Space leans a little harder on execution, though the gap is small.
Half-Life 2
Gravity gun and shooting demand precision.
Nyan Cat: Lost In Space
Precise dodging and platform timing decides survival
Half-Life 2 leans a little harder on reads, though the gap is small.
Half-Life 2
Combine AI scripted, non-adaptive.
Nyan Cat: Lost In Space
No opponent to predict; scripted hazards
Nyan Cat: Lost In Space leans clearly harder on variance.
Half-Life 2
Almost no randomness.
Nyan Cat: Lost In Space
Procedural obstacle layouts add some unpredictability
Nyan Cat: Lost In Space leans a little harder on optimization, though the gap is small.
Half-Life 2
Linear progression with no builds.
Nyan Cat: Lost In Space
Upgrade choices and route knowledge improve runs
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.