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

Execution · Pure Mechanics
Dodging scripted bullet patterns with stage memorisation doing the planning.

Execution · Pure Mechanics
Landmark FPS built on physics puzzles and tight gunplay.
Air Buster leans Execution (Pure Mechanics); Half-Life 2 leans Execution (Pure Mechanics).
Air Buster leans clearly harder on execution.
Air Buster
Bullet weaving and tight corridors demand precise control
Half-Life 2
Gravity gun and shooting demand precision.
Half-Life 2 leans a little harder on reads, though the gap is small.
Air Buster
Enemy waves are fully scripted patterns
Half-Life 2
Combine AI scripted, non-adaptive.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Air Buster
Spawns are deterministic once a credit is studied
Half-Life 2
Almost no randomness.
Air Buster leans clearly harder on optimization.
Air Buster
Memorising stage layouts and power-up routes drives clears
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.