head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Pure Mechanics
Retro arcade racer channeling Top Gear's pure lane-weaving speed.

Execution · Pure Mechanics
Arcade racing lines and traffic-dodging reflexes on memorisable tracks.
Horizon Chase Turbo leans Execution (Pure Mechanics); Test Drive 6 leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Horizon Chase Turbo
Weaving through traffic and nailing fuel pickups
Test Drive 6
Cornering at speed through traffic is the entire challenge
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Horizon Chase Turbo
Rival cars run fixed rubber-band logic
Test Drive 6
AI racers follow rubber-band scripts, not minds to model
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Horizon Chase Turbo
Minimal randomness in track layouts
Test Drive 6
Traffic adds mild unpredictability to known tracks
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Horizon Chase Turbo
Car stats and lap memorization help
Test Drive 6
Learning racing lines and car choice is solvable
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.