head to head
Neither is simply harder - they are hard in different places. DmC: Devil May Cry demands more execution; Grand Theft Auto V demands more reads.

Execution · Practiced Mastery
Ninja Theory's stylish-action reboot with angel-demon stance switching through a shifting Limbo.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
DmC: Devil May Cry leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
DmC: Devil May Cry leans clearly harder on execution.
DmC: Devil May Cry
Angel/demon stance weaving is demanding but softer than mainline
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto V leans clearly harder on reads.
DmC: Devil May Cry
Color-coded enemies dictate fixed answers
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Grand Theft Auto V leans a little harder on variance, though the gap is small.
DmC: Devil May Cry
Limbo levels are authored spectacle, not random
Grand Theft Auto V
Some mission and lobby randomness.
DmC: Devil May Cry leans clearly harder on optimization.
DmC: Devil May Cry
Color-coding turns encounters into solvable matching puzzles
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.