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
Tests off-road handling and freeform route choice across an enormous open map.

Execution · Pure Mechanics
Arcade driving that tests cornering execution over a small set of memorisable tracks.
Fuel leans Execution (Pure Mechanics); Need for Speed II 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.
Fuel
Off-road vehicle control through weather events is the core test
Need for Speed II
Cornering and throttle control decide every race
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
Need for Speed II
AI racers follow rubber-banded scripts, not minds
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fuel
The huge map is scripted-but-unknown until explored
Need for Speed II
Tracks are fixed; nothing meaningful is hidden
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fuel
Route choice across open terrain rewards planning
Need for Speed II
Learning six tracks' racing lines and car 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.