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 · Competitive PvP
Artillery touch, human prediction and weapon economy in destructible 3D terrain.

Execution · Competitive PvP
Tests trajectory aim and turn planning against human targets amid crate luck.
Worms 3D leans Execution (Competitive PvP); Worms: Ultimate Mayhem leans Execution (Competitive PvP).
Worms: Ultimate Mayhem leans a little harder on execution, though the gap is small.
Worms 3D
Judging grenade arcs and wind in 3D takes real touch
Worms: Ultimate Mayhem
3D grenade arcs and ninja-rope control reward practiced aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Worms 3D
Predicting where a human hides and strikes next matters
Worms: Ultimate Mayhem
Predicting a human's target priorities shapes each turn
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Worms 3D
Wind, crate drops and terrain chaos swing turns
Worms: Ultimate Mayhem
Crate drops, wind and terrain chaos swing rounds
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Worms 3D
Weapon economy and positioning math reward planning
Worms: Ultimate Mayhem
Weapon economy and positioning are plannable each turn
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.