head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

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

Execution · Practiced Mastery
Soulslike shooter where procedurally rolled campaigns randomize bosses and loot.
Left 4 Dead leans Execution (Twitch Chaos); Remnant: From the Ashes leans Execution (Practiced Mastery).
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
Remnant: From the Ashes
Souls-style dodging fused with sustained gun accuracy.
Left 4 Dead leans a little harder on reads, though the gap is small.
Left 4 Dead
Versus mode adds human ambush mindgames
Remnant: From the Ashes
Bosses are scripted movesets despite feeling adversarial.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Left 4 Dead
AI Director randomizes hordes, items, and specials
Remnant: From the Ashes
Procedurally rolled worlds, bosses, and item availability.
Remnant: From the Ashes leans a little harder on optimization, though the gap is small.
Left 4 Dead
Team spacing, route choice, and resource discipline
Remnant: From the Ashes
Build crafting and learned boss patterns converge to mastery.
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.