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

Execution · Practiced Mastery
Toy-car arcade racer about drift-charging boost on loop-the-loop tracks.

Execution · Practiced Mastery
Aggressive circuit racing testing car control over memorisable tracks and braking points.
Hot Wheels Unleashed leans Execution (Practiced Mastery); Race Driver: Grid leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Hot Wheels Unleashed
Drift-boost management on twisting plastic tracks
Race Driver: Grid
Aggressive wheel-to-wheel car control is the core demand
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Hot Wheels Unleashed
Online races add light human jockeying
Race Driver: Grid
Online racing adds light opponent positioning awareness
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Hot Wheels Unleashed
Car unboxing randomness outside races
Race Driver: Grid
Damage outcomes add slight unpredictability to contact
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Hot Wheels Unleashed
Car tiers, upgrades, and racing lines
Race Driver: Grid
Braking points, lines and flashback management are learnable
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.