head to head
Neither is simply harder - they are hard in different places. Mortal Kombat 1 demands more reads; StarCraft demands more optimization.

Execution · Grand Arena
A tag-assisted fighter blending execution with read-based mixups.

Optimization · Grand Arena
A real-time strategy classic where perfected build orders and mechanical speed decide most matches.
Mortal Kombat 1 leans Execution (Grand Arena); StarCraft leans Optimization (Grand Arena).
Mortal Kombat 1 leans a little harder on execution, though the gap is small.
Mortal Kombat 1
Kameo timing and combo execution gate damage.
StarCraft
APM and micro control ceiling is huge
Mortal Kombat 1 leans clearly harder on reads.
Mortal Kombat 1
Adaptive opponents bait pokes and wakeups.
StarCraft
scouting and predicting human opponent builds
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mortal Kombat 1
Effectively no randomness in matches.
StarCraft
minimal hidden info beyond fog of war
StarCraft leans clearly harder on optimization.
Mortal Kombat 1
Kameo synergy, frame data, and punish theory.
StarCraft
build orders and economy are near-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.