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 · Practiced Mastery
Co-op zombie shooter with adaptive AI Director.

Optimization · Practiced Mastery
A blocky free-to-play zombie survival sandbox mixing scavenging, basebuilding, and PvP.
Left 4 Dead 2 leans Execution (Practiced Mastery); Unturned leans Optimization (Practiced Mastery).
Left 4 Dead 2 leans a little harder on execution, though the gap is small.
Left 4 Dead 2
Headshots under horde pressure need aim
Unturned
Gunfights and driving reward aim and control
Unturned leans a little harder on reads, though the gap is small.
Left 4 Dead 2
Versus special-infected ambushes have reads
Unturned
Human raiders and ambushes on PvP servers
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Left 4 Dead 2
AI Director randomizes spawns and items
Unturned
Loot spawns and unknown player positions
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Left 4 Dead 2
Route knowledge and weapon picks solvable
Unturned
Base building, loot routes, and crafting economy
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.