head to head
Neither is simply harder - they are hard in different places. Call of Duty: Modern Warfare 2 demands more variance; Street Fighter II' Turbo demands more reads.

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

Execution · Competitive PvP
The foundational test of fighting-game execution and human prediction at speed.
Call of Duty: Modern Warfare 2 leans Execution (Competitive PvP); Street Fighter II' Turbo 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: Modern Warfare 2
Fast time-to-kill rewards raw aim and reflex
Street Fighter II' Turbo
Charge timing and anti-air reactions at turbo speed
Street Fighter II' Turbo leans clearly harder on reads.
Call of Duty: Modern Warfare 2
Outguessing human rotations and flanks
Street Fighter II' Turbo
Fireball-trap mind games against an adapting human are the essence
Call of Duty: Modern Warfare 2 leans clearly harder on variance.
Call of Duty: Modern Warfare 2
Spawn flips and killstreak randomness
Street Fighter II' Turbo
Twelve public movesets, nothing hidden
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Modern Warfare 2
Killstreak economy, loadout and map knowledge
Street Fighter II' Turbo
Matchup theory and spacing fundamentals were codified here
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.