head to head
Grand Theft Auto V asks more than Super Mario Galaxy, and the gap is reads.

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

Execution · Practiced Mastery
Mid-demand 3D platforming execution across fixed gravity puzzles.
Grand Theft Auto V leans Execution (Practiced Mastery); Super Mario Galaxy leans Execution (Practiced Mastery).
Super Mario Galaxy leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Super Mario Galaxy
Gravity-bending jumps need timing, though forgiving by Mario standards
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Super Mario Galaxy
Bosses repeat fixed patterns - nothing adapts
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Super Mario Galaxy
Galaxies are scripted; surprises evaporate after one visit
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Heists, money loops, builds learnable.
Super Mario Galaxy
Star routes and comet challenges reward learned solutions
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.