head to head
Guild Wars 2 asks more than Castle Crashers, and the gap is optimization.

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

Optimization · Practiced Mastery
Active dodge-heavy combat with a deep build system, tested against both scripted content and human opponents.
Castle Crashers leans Execution (Practiced Mastery); Guild Wars 2 leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Castle Crashers
Combo execution and crowd-control timing are the performance ceiling
Guild Wars 2
Dodge timing and active combat define moment-to-moment play
Guild Wars 2 leans a little harder on reads, though the gap is small.
Castle Crashers
PvP arenas add light human-opponent reads
Guild Wars 2
WvW and structured PvP feature real adaptive opponents
Guild Wars 2 leans a little harder on variance, though the gap is small.
Castle Crashers
Enemy spawns follow scripted patterns with minimal randomness
Guild Wars 2
Loot RNG is present but secondary to skill expression
Guild Wars 2 leans clearly harder on optimization.
Castle Crashers
Levelling investment, magic loadout, and pet choice are optimisable
Guild Wars 2
Build crafting and rotation theory-crafting reward deep analysis
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.