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
Classic fighting execution and human prediction atop a famously unbalanced roster.

Execution · Competitive PvP
Territory control through shooter execution and constant prediction of adapting human teams.
Mortal Kombat Trilogy leans Execution (Competitive PvP); Splatoon leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Mortal Kombat Trilogy
Dial-a-combo inputs and run-meter pressure demand fast hands
Splatoon
Aim, swim-form movement and ink management are constant demands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mortal Kombat Trilogy
Human opponents must be baited into unsafe moves
Splatoon
Human opponents adapt flanks and pushes every match
Splatoon leans a little harder on variance, though the gap is small.
Mortal Kombat Trilogy
Movesets are public; nothing hidden in a match
Splatoon
Hidden squids in ink create momentary information gaps
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mortal Kombat Trilogy
Knowing the bloated roster's broken tech is half the battle
Splatoon
Weapon kits, map control timing and gear builds 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.