head to head
Neither is simply harder - they are hard in different places. Borderlands 2 demands more execution; Buckshot Roulette demands more reads.

Optimization · Systems & Chaos
Loot-shooter RPG built on gear chasing.

Variance · Systems & Chaos
A tense one-on-one Russian roulette duel with a shotgun.
Borderlands 2 leans Optimization (Systems & Chaos); Buckshot Roulette leans Variance (Systems & Chaos).
Borderlands 2 leans clearly harder on execution.
Borderlands 2
Aim matters but generous hit feel
Buckshot Roulette
Trivial click inputs.
Buckshot Roulette leans clearly harder on reads.
Borderlands 2
Enemies are scripted loot fodder
Buckshot Roulette
Dealer has minor adaptive bluff tells.
Buckshot Roulette leans a little harder on variance, though the gap is small.
Borderlands 2
Procedurally generated weapon drops vary
Buckshot Roulette
Shell order is hidden and random.
Borderlands 2 leans clearly harder on optimization.
Borderlands 2
Skill trees and gear math heavily solved
Buckshot Roulette
Probability tracking and item use reward optimization.
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.