head to head
Tennis World Tour 2 asks more than Half-Life 2, and the gap is reads.

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

Execution · Pure Mechanics
A tennis simulation testing shot execution and reading opponent positioning.
Half-Life 2 leans Execution (Pure Mechanics); Tennis World Tour 2 leans Execution (Pure Mechanics).
Tennis World Tour 2 leans clearly harder on execution.
Half-Life 2
Gravity gun and shooting demand precision.
Tennis World Tour 2
shot timing, positioning, and precision control
Tennis World Tour 2 leans clearly harder on reads.
Half-Life 2
Combine AI scripted, non-adaptive.
Tennis World Tour 2
human opponents adapt shot placement
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.
Tennis World Tour 2
minor ball-physics unpredictability
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.
Tennis World Tour 2
minor player/equipment choice
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.