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 · Twitch Chaos
Co-op zombie shooter whose AI Director reshuffles every run to keep teams honest.

Execution · Pure Mechanics
An arcade maze shooter where players blast monsters and, occasionally, each other.
Left 4 Dead leans Execution (Twitch Chaos); Wizard of Wor 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.
Left 4 Dead
Headshots, melee shoves, and special-infected reaction time
Wizard of Wor
Quick corridor shootouts reward reaction speed
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Left 4 Dead
Versus mode adds human ambush mindgames
Wizard of Wor
Two-player mode lets partners turn on each other
Left 4 Dead leans a little harder on variance, though the gap is small.
Left 4 Dead
AI Director randomizes hordes, items, and specials
Wizard of Wor
Invisible monsters and the warping Worluk hide information
Left 4 Dead leans a little harder on optimization, though the gap is small.
Left 4 Dead
Team spacing, route choice, and resource discipline
Wizard of Wor
Maze control strategies converge with play
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.