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
Co-op first-person zombie RPG about improvised weapons on a resort island.

Optimization · Practiced Mastery
A Marvel team brawler where picking the right hero combos and fusions does the winning.
Dead Island leans Optimization (Practiced Mastery); Marvel Ultimate Alliance 2 leans Optimization (Practiced Mastery).
Dead Island leans a little harder on execution, though the gap is small.
Dead Island
first-person melee timing and stamina
Marvel Ultimate Alliance 2
Fusion timing and brawling are accessible.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Dead Island
zombies are scripted swarms
Marvel Ultimate Alliance 2
Fully scripted PvE encounters.
Dead Island leans a little harder on variance, though the gap is small.
Dead Island
weapon drops and spawns add noise
Marvel Ultimate Alliance 2
Small randomness in boosts and drops.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Dead Island
weapon mods and skill builds carry late game
Marvel Ultimate Alliance 2
Roster synergy and fusion choices are the real lever.
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.