head to head
Call of Duty: Modern Warfare 2 asks more than FIFA Soccer 08, and the gap is optimization.

Execution · Competitive PvP
Blockbuster 2009 sequel famous for killstreak chains and frantic multiplayer.

Execution · Competitive PvP
Stick execution and outguessing a human defender, with tactics underneath.
Call of Duty: Modern Warfare 2 leans Execution (Competitive PvP); FIFA Soccer 08 leans Execution (Competitive PvP).
Call of Duty: Modern Warfare 2 leans a little harder on execution, though the gap is small.
Call of Duty: Modern Warfare 2
Fast time-to-kill rewards raw aim and reflex
FIFA Soccer 08
Dribbling, timing tackles and finishing reward stick skill
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
Outguessing human rotations and flanks
FIFA Soccer 08
Versus humans, baiting defenders and disguising attacks is core
Call of Duty: Modern Warfare 2 leans a little harder on variance, though the gap is small.
Call of Duty: Modern Warfare 2
Spawn flips and killstreak randomness
FIFA Soccer 08
Ball physics adds bounce noise to single matches
Call of Duty: Modern Warfare 2 leans clearly harder on optimization.
Call of Duty: Modern Warfare 2
Killstreak economy, loadout and map knowledge
FIFA Soccer 08
Formations and squad selection matter but stay shallow
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.