head to head
Mortal Shell asks more than Grand Theft Auto V, and the gap is execution.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.

Execution · Practiced Mastery
A lean souls-like carried by hardened-parry timing and shell selection.
Grand Theft Auto V leans Execution (Practiced Mastery); Mortal Shell leans Execution (Practiced Mastery).
Mortal Shell leans clearly harder on execution.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Mortal Shell
Hardened parry timing demands inputs
Grand Theft Auto V leans a little harder on reads, though the gap is small.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Mortal Shell
Scripted bosses
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Mortal Shell
Minor item randomness
Mortal Shell leans clearly harder on optimization.
Grand Theft Auto V
Heists, money loops, builds learnable.
Mortal Shell
Shell choice and upgrade routing matter
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.