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
A long Viking RPG carried by exploration and gear progression.

Execution · Practiced Mastery
Robot-dinosaur hunting that rewards weak-point study and ranged precision.
Assassin's Creed Valhalla leans Optimization (Practiced Mastery); Horizon Zero Dawn leans Execution (Practiced Mastery).
Horizon Zero Dawn leans a little harder on execution, though the gap is small.
Assassin's Creed Valhalla
Combat timing matters but forgiving.
Horizon Zero Dawn
Bow aiming and dodge timing matter.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Assassin's Creed Valhalla
Enemies scripted and predictable.
Horizon Zero Dawn
Machines follow fixed patterns, not adapting.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Assassin's Creed Valhalla
Loot rolls and raid encounters vary mildly.
Horizon Zero Dawn
Some loot and patrol randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Assassin's Creed Valhalla
Skill tree, gear, raid routing solvable.
Horizon Zero Dawn
Weak points, traps, builds fully solvable.
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.