head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Execution · Pure Mechanics
Tests off-road handling and freeform route choice across an enormous open map.

Execution · Practiced Mastery
An isometric combat racer set to metal covers, mixing vehicle upgrades with weaponized laps.
Fuel leans Execution (Pure Mechanics); Rock n' Roll Racing 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.
Fuel
Off-road vehicle control through weather events is the core test
Rock n' Roll Racing
Isometric cornering and weapon timing carry races.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fuel
AI racers rubber-band on scripts; online is thin
Rock n' Roll Racing
Two-player duels add slight prediction; AI is scripted.
Rock n' Roll Racing leans a little harder on variance, though the gap is small.
Fuel
The huge map is scripted-but-unknown until explored
Rock n' Roll Racing
Weapon exchanges and pickups create chaos.
Rock n' Roll Racing leans a little harder on optimization, though the gap is small.
Fuel
Route choice across open terrain rewards planning
Rock n' Roll Racing
Upgrade purchases and planet-by-planet earnings are plannable.
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.