head to head
StarCraft II: Wings of Liberty asks more than Call of Duty: Modern Warfare II, and the gap is reads.

Execution · Grand Arena
Modern arena shooter built on aim and loadouts.

Execution · Grand Arena
Real-time strategy where hands, reads, and build optimization all matter at the top.
Call of Duty: Modern Warfare II leans Execution (Grand Arena); StarCraft II: Wings of Liberty leans Execution (Grand Arena).
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 II
Sub-second TTK demands precise tracking
StarCraft II: Wings of Liberty
APM, macro, micro-control under pressure
StarCraft II: Wings of Liberty leans clearly harder on reads.
Call of Duty: Modern Warfare II
Holding angles vs aggression is mind game
StarCraft II: Wings of Liberty
1v1 ladder vs adaptive humans modeling you
Call of Duty: Modern Warfare II leans a little harder on variance, though the gap is small.
Call of Duty: Modern Warfare II
Spawn logic and SBMM shuffle outcomes
StarCraft II: Wings of Liberty
map spawns minor; mostly known
StarCraft II: Wings of Liberty leans clearly harder on optimization.
Call of Duty: Modern Warfare II
Gunsmith attachments and perk packages
StarCraft II: Wings of Liberty
build orders, economy curves heavily solved
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.