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.

Optimization · Pure Optimization
Instanced online RPG where deck-like eight-skill builds decide battles before they begin.

Optimization · Practiced Mastery
Trap-maze economics against human attackers who adapt their pushes.
Guild Wars leans Optimization (Pure Optimization); Orcs Must Die! Unchained leans Optimization (Practiced Mastery).
Orcs Must Die! Unchained leans a little harder on execution, though the gap is small.
Guild Wars
Interrupt timing and kiting in skirmishes
Orcs Must Die! Unchained
Third-person combat matters but traps do the killing
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Guild Wars
GvG and arena metagame against adapting humans
Orcs Must Die! Unchained
PvP sieges reward predicting enemy pushes and trap placement
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Guild Wars
Modest drop and spawn randomness
Orcs Must Die! Unchained
Card draws and minion waves add mild noise
Guild Wars leans a little harder on optimization, though the gap is small.
Guild Wars
Eight-skill build construction is the game's soul
Orcs Must Die! Unchained
Trap economy and maze layout theory decide fortresses
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.