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 · Grand Arena
A combo system built on constant Combo Breaker mind-games that create a unique adaptive read-off at every moment of a combo.

Execution · Grand Arena
A 3D fighter where movement and mixup reads decide rounds.
Killer Instinct (2013) leans Execution (Grand Arena); Tekken 8 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.
Killer Instinct (2013)
Shadow counters and Combo Breaker timing demand very precise inputs
Tekken 8
Just-frame inputs and 3D movement punish sloppy hands.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Killer Instinct (2013)
Combo Breaker prediction is a pure read-off against an adaptive opponent
Tekken 8
Adaptive opponents mix lows, highs, and throws.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Killer Instinct (2013)
No RNG; all mechanics are fully visible
Tekken 8
Negligible RNG in core matches.
Killer Instinct (2013) leans a little harder on optimization, though the gap is small.
Killer Instinct (2013)
Instinct activation timing and optimal opener routes are well-studied
Tekken 8
Frame data, punishes, and movelist depth.
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.