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

Execution · Competitive PvP
A test of precise inputs and constant human prediction across a fixed roster of matchup puzzles.

Execution · Grand Arena
Frame-perfect execution fused with constant prediction of an adapting human opponent.
Street Fighter II: The World Warrior leans Execution (Competitive PvP); Ultra Street Fighter IV 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: The World Warrior
Frame-precise inputs and combo timing define every matchup
Ultra Street Fighter IV
One-frame links and FADC timing set a brutal hands ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter II: The World Warrior
Predicting human opponent's next move is constant and non-convergent
Ultra Street Fighter IV
Footsies and conditioning the human opponent is the core duel
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Street Fighter II: The World Warrior
No meaningful RNG; match outcomes are skill-determined
Ultra Street Fighter IV
Almost nothing hidden once both characters are known
Ultra Street Fighter IV leans a little harder on optimization, though the gap is small.
Street Fighter II: The World Warrior
Character matchups and punish routes are learnable but not fully solvable
Ultra Street Fighter IV
Frame data, matchups and option-selects form deep studied theory
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.