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 · Practiced Mastery
Soft-body physics sandbox driving and crashing.

Execution · Twitch Chaos
Kart racing with random item pickups and drift timing on themed tracks.
BeamNG.drive leans Execution (Practiced Mastery); Madagascar Kartz leans Execution (Twitch Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
BeamNG.drive
Soft-body physics car control
Madagascar Kartz
Steering, drifting and item timing matter in races
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
BeamNG.drive
Mostly sandbox, no adaptive opponents
Madagascar Kartz
Rubber-band AI is scripted, not adaptive prediction
Madagascar Kartz leans a little harder on variance, though the gap is small.
BeamNG.drive
Emergent crash physics outcomes
Madagascar Kartz
Random item pickups swing race outcomes
BeamNG.drive leans a little harder on optimization, though the gap is small.
BeamNG.drive
Vehicle tuning, scenario routing
Madagascar Kartz
Track shortcuts and item management reward knowledge
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.