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
A classic beat-em-up demanding execution against scripted enemy waves.

Execution · Pure Mechanics
Light-gun aim speed against fixed enemy waves on Mario-themed rails.
Teenage Mutant Ninja Turtles III: The Manhattan Project leans Execution (Pure Mechanics); Yoshi's Safari 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.
Teenage Mutant Ninja Turtles III: The Manhattan Project
beat-em-up timing and enemy juggling
Yoshi's Safari
Super Scope aim speed and accuracy is the entire test
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Teenage Mutant Ninja Turtles III: The Manhattan Project
enemies run simple fixed scripts
Yoshi's Safari
Enemies attack on fixed choreography
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Teenage Mutant Ninja Turtles III: The Manhattan Project
minor enemy spawn randomness
Yoshi's Safari
Stages play identically every run
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Teenage Mutant Ninja Turtles III: The Manhattan Project
character choice and route memorization
Yoshi's Safari
Memorising boss weak points and wave order helps
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.
full breakdown
Teenage Mutant Ninja Turtles III: The Manhattan Project →
full breakdown
Yoshi's Safari →