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
The 70s-cinema getaway driving game with famously demanding physics.

Execution · Pure Mechanics
Tests horde-dodging execution and inventive weapon-stack loadouts in 2D shooter chaos.
Driver leans Execution (Pure Mechanics); Serious Sam Double D XXL 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.
Driver
Handbrake control and pursuit driving by feel
Serious Sam Double D XXL
Dodging horde fire while managing gunstacks demands constant motion
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Driver
Police AI is mappable
Serious Sam Double D XXL
Enemies charge in scripted waves
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Driver
Traffic adds mild unpredictability
Serious Sam Double D XXL
Fixed spawns, deterministic chaos
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Driver
City routes and mission tactics learnable
Serious Sam Double D XXL
Gunstacker loadout combinations reward experimentation
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.