head to head
Neither is simply harder - they are hard in different places. Children of Morta demands more variance; Grand Theft Auto V demands more reads.

Optimization · Practiced Mastery
Family-focused action roguelike with persistent narrative progression between runs.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Children of Morta leans Optimization (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Children of Morta
Action combat with dodges and combos but forgiving timing.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto V leans clearly harder on reads.
Children of Morta
Enemies are scripted hack-and-slash fodder.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Children of Morta leans clearly harder on variance.
Children of Morta
Procedural floors and drops add modest swing.
Grand Theft Auto V
Some mission and lobby randomness.
Children of Morta leans clearly harder on optimization.
Children of Morta
Family upgrade tree and character synergies reward planning.
Grand Theft Auto V
Heists, money loops, builds learnable.
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.