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.

Optimization · Practiced Mastery
The original loot-driven co-op shooter set on the bandit world of Pandora.

Optimization · Pure Optimization
Crafting-tree planning and needs management under light zombie pressure.
Borderlands leans Optimization (Practiced Mastery); How to Survive leans Optimization (Pure Optimization).
Borderlands leans a little harder on execution, though the gap is small.
Borderlands
Standard FPS aim; numbers matter more than precision
How to Survive
Twin-stick zombie kiting needs modest aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Borderlands
Bandits and skags are scripted
How to Survive
Zombies are mindless scripted pressure
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Borderlands
Procedural loot drops gate your power
How to Survive
Scavenged materials and island layouts are unknown until explored
How to Survive leans a little harder on optimization, though the gap is small.
Borderlands
Builds, gear math, and farming routes dominate
How to Survive
Crafting trees and needs management decide survival
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.