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 · Pure Mechanics
The NES light-gun classic of shooting ducks and enduring the dog.

Execution · Pure Mechanics
A light reflex test of steering past obstacles until the yeti wins.
Duck Hunt leans Execution (Pure Mechanics); SkiFree leans Execution (Pure Mechanics).
Duck Hunt leans a little harder on execution, though the gap is small.
Duck Hunt
Pure light-gun aim and reaction speed
SkiFree
Dodging trees and outrunning the yeti is pure reaction steering
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Duck Hunt
Ducks fly on simple patterns
SkiFree
The snowman is scripted pursuit, not an adapting mind
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Duck Hunt
Flight paths vary a little
SkiFree
Obstacle placement varies run to run but stays shallow
SkiFree leans a little harder on optimization, though the gap is small.
Duck Hunt
Almost nothing to optimise beyond aim
SkiFree
Beyond slalom lines there is little system to solve
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.