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.

Execution · Competitive PvP
Cold War-era shooter pairing twitch multiplayer with the cult Zombies mode.

Execution · Competitive PvP
Fast aim duels plus predicting human movement on memorised maps.
Call of Duty: Black Ops leans Execution (Competitive PvP); Call of Duty: Modern Warfare Remastered leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Black Ops
Gunfights hinge on aim and reaction speed
Call of Duty: Modern Warfare Remastered
Snap aim and reaction time dominate every gunfight
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Black Ops
Reading human opponents' positioning and timing
Call of Duty: Modern Warfare Remastered
Online opponents rotate and adapt; pre-aiming them is prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Black Ops
Spawns, care packages, zombies RNG
Call of Duty: Modern Warfare Remastered
Spawns and random lobbies inject per-match noise
Call of Duty: Black Ops leans a little harder on optimization, though the gap is small.
Call of Duty: Black Ops
Class builds, map control, zombies routing
Call of Duty: Modern Warfare Remastered
Map control, loadouts and timing form a learnable meta
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.