head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Practiced Mastery
A brawler that tests combo execution and crowd management across linear gauntlets, with a light optimisation layer from its RPG progression.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Castle Crashers leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Castle Crashers leans a little harder on execution, though the gap is small.
Castle Crashers
Combo execution and crowd-control timing are the performance ceiling
Grand Theft Auto V
Driving and shooting demand decent inputs.
Castle Crashers leans a little harder on reads, though the gap is small.
Castle Crashers
PvP arenas add light human-opponent reads
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Castle Crashers
Enemy spawns follow scripted patterns with minimal randomness
Grand Theft Auto V
Some mission and lobby randomness.
Castle Crashers leans a little harder on optimization, though the gap is small.
Castle Crashers
Levelling investment, magic loadout, and pet choice are optimisable
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.