head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, 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
Scheduling and routing a fixed 72-hour clock through zombie-filled detours.
Dead Island leans Optimization (Practiced Mastery); Dead Rising 2 leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Dead Island
first-person melee timing and stamina
Dead Rising 2
Crowd-clearing combat needs competence, not twitch mastery
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
Dead Rising 2
Zombies and psychopaths follow fixed behaviour
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dead Island
weapon drops and spawns add noise
Dead Rising 2
Survivor events are scripted-but-unknown on first runs
Dead Rising 2 leans a little harder on optimization, though the gap is small.
Dead Island
weapon mods and skill builds carry late game
Dead Rising 2
The 72-hour clock makes scheduling and routing the real game
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.