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

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

Execution · Practiced Mastery
Precision sniping and arena navigation through fixed, gimmick-laden levels.
Grand Theft Auto V leans Execution (Practiced Mastery); MDK leans Execution (Practiced Mastery).
MDK leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
MDK
Sniper-mode precision and arena dodging demand steady hands
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
MDK
Alien enemies behave on fixed scripts
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
MDK
Levels are authored with nothing random
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.
MDK
Learning arena gimmicks and item use solves each level
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.