head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Execution · Competitive PvP
The foundational test of fighting-game execution and human prediction at speed.

Execution · Grand Arena
A refined KOF entry that lowers the execution bar slightly while preserving the team-order reads and punish game.
Street Fighter II' Turbo leans Execution (Competitive PvP); The King of Fighters XV 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.
Street Fighter II' Turbo
Charge timing and anti-air reactions at turbo speed
The King of Fighters XV
Shatter Strike and MAX Mode combos demand practiced precise inputs
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter II' Turbo
Fireball-trap mind games against an adapting human are the essence
The King of Fighters XV
Team order choices and opponent habit exploitation remain central
The King of Fighters XV leans a little harder on variance, though the gap is small.
Street Fighter II' Turbo
Twelve public movesets, nothing hidden
The King of Fighters XV
No RNG; all information is visible in the match
The King of Fighters XV leans a little harder on optimization, though the gap is small.
Street Fighter II' Turbo
Matchup theory and spacing fundamentals were codified here
The King of Fighters XV
Team construction and MAX Mode routing reward study
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.