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.

Execution · Practiced Mastery
Aim and spawn memorisation through a fully scripted cinematic campaign.

Execution · Pure Mechanics
A simple arcade rail shooter testing aim and reaction against scripted waves.
Call of Duty: Modern Warfare 2 Campaign Remastered leans Execution (Practiced Mastery); Sky Destroyer leans Execution (Pure Mechanics).
Sky Destroyer leans a little harder on execution, though the gap is small.
Call of Duty: Modern Warfare 2 Campaign Remastered
Aim and reaction carry every scripted firefight
Sky Destroyer
Aiming and dodging on rails is the entire test
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 2 Campaign Remastered
Enemies spawn and behave on fixed scripts
Sky Destroyer
Enemy planes fly scripted attack runs
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 2 Campaign Remastered
Set-piece campaign with almost nothing random
Sky Destroyer
Stages repeat predictably once seen
Call of Duty: Modern Warfare 2 Campaign Remastered leans a little harder on optimization, though the gap is small.
Call of Duty: Modern Warfare 2 Campaign Remastered
Learning spawns and cover lines trivialises veteran difficulty
Sky Destroyer
Little to plan beyond learning spawn patterns
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.