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

Execution · Twitch Chaos
Item-luck kart racing with a creation suite bolted on.

Execution · Pure Mechanics
Demolition derby racer with destructible PvP chaos.
LittleBigPlanet Karting leans Execution (Twitch Chaos); Wreckfest leans Execution (Pure Mechanics).
Wreckfest leans a little harder on execution, though the gap is small.
LittleBigPlanet Karting
Drifting and weapon timing decide most races
Wreckfest
Demolition driving, ramming angles
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
LittleBigPlanet Karting
Human racers add light prediction in item battles
Wreckfest
Online derby PvP rewards ramming reads
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
LittleBigPlanet Karting
Random item pickups swing positions constantly
Wreckfest
Crash physics chaos
Wreckfest leans a little harder on optimization, though the gap is small.
LittleBigPlanet Karting
Track lines and shortcut knowledge give a modest edge
Wreckfest
Car upgrades and durability tuning
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.