Building comparison
head to head
Left 4 DeadvsZombie Tsunami
Left 4 Dead asks more than Zombie Tsunami, and the gap is reads.
Left 4 Dead
Execution · Twitch Chaos
Co-op zombie shooter whose AI Director reshuffles every run to keep teams honest.
Zombie Tsunami
Execution · Twitch Chaos
One-touch reflex timing against procedurally generated obstacle streams.
Left 4 Dead leans Execution (Twitch Chaos); Zombie Tsunami leans Execution (Twitch Chaos).
Left 4 DeadZombie Tsunami
Axis by axis
Execution7 vs 6
Left 4 Dead leans a little harder on execution, though the gap is small.
Left 4 Dead
Headshots, melee shoves, and special-infected reaction time
Zombie Tsunami
One-touch jump timing for a growing horde is the whole test
Reads2 vs 0
Left 4 Dead leans clearly harder on reads.
Left 4 Dead
Versus mode adds human ambush mindgames
Zombie Tsunami
No opponent - obstacles are procedural
Variance5 vs 4
Left 4 Dead leans a little harder on variance, though the gap is small.
Left 4 Dead
AI Director randomizes hordes, items, and specials
Zombie Tsunami
Procedural level generation decides what each run offers
Optimization5 vs 3
Left 4 Dead leans clearly harder on optimization.
Left 4 Dead
Team spacing, route choice, and resource discipline
Zombie Tsunami
Upgrade spending is a thin meta layer
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.