head to head
Neither is simply harder - they are hard in different places. Endless Dungeon demands more variance; Grand Theft Auto V demands more reads.

Execution · Practiced Mastery
Roguelite blending twin-stick shooting with tower-defense crystal escorts.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Endless Dungeon leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Endless Dungeon leans a little harder on execution, though the gap is small.
Endless Dungeon
Twin-stick shooting during wave defenses
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto V leans clearly harder on reads.
Endless Dungeon
Monster waves follow spawn rules, not adaptation
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Endless Dungeon leans clearly harder on variance.
Endless Dungeon
Procedural floors and random resource rooms
Grand Theft Auto V
Some mission and lobby randomness.
Endless Dungeon leans clearly harder on optimization.
Endless Dungeon
Turret placement and route economy planning
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.