head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Optimization · Practiced Mastery
A Revolution-era Paris entry built around dense crowds and open-ended blackbox assassinations.

Optimization · Practiced Mastery
Co-op superhero brawler about assembling the right four-hero squad and builds.
Assassin's Creed Unity leans Optimization (Practiced Mastery); Marvel: Ultimate Alliance 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.
Assassin's Creed Unity
Refined parkour, still forgiving combat
Marvel: Ultimate Alliance
brawling and dodge timing are forgiving
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Assassin's Creed Unity
Co-op partners face scripted guards
Marvel: Ultimate Alliance
enemies are scripted mobs
Marvel: Ultimate Alliance leans a little harder on variance, though the gap is small.
Assassin's Creed Unity
Fixed sandbox assassinations
Marvel: Ultimate Alliance
some loot and unlock randomness
Marvel: Ultimate Alliance leans a little harder on optimization, though the gap is small.
Assassin's Creed Unity
Gear builds and blackbox approach planning
Marvel: Ultimate Alliance
team bonuses, gear, and skill builds carry difficulty
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.