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

Execution · Competitive PvP
A combo-centric fighting game built around the breaker guessing game.

Execution · Competitive PvP
A test of precise inputs and constant human prediction across a fixed roster of matchup puzzles.
Killer Instinct leans Execution (Competitive PvP); Street Fighter II: The World Warrior leans Execution (Competitive PvP).
Street Fighter II: The World Warrior leans a little harder on execution, though the gap is small.
Killer Instinct
Long combo execution and breaker timing
Street Fighter II: The World Warrior
Frame-precise inputs and combo timing define every matchup
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Killer Instinct
Combo-breaker guessing is a live mind game
Street Fighter II: The World Warrior
Predicting human opponent's next move is constant and non-convergent
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Killer Instinct
Full information fighter
Street Fighter II: The World Warrior
No meaningful RNG; match outcomes are skill-determined
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Killer Instinct
Frame data and matchup study
Street Fighter II: The World Warrior
Character matchups and punish routes are learnable but not fully solvable
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.