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 · Practiced Mastery
A strategy shooter testing defense placement economy backed by active gunplay.

Optimization · Pure Optimization
A third-person tower defense about funneling orc hordes into gleefully lethal trap corridors.
Fortified leans Optimization (Practiced Mastery); Orcs Must Die! leans Optimization (Pure Optimization).
Fortified leans a little harder on execution, though the gap is small.
Fortified
Third-person shooting between waves keeps hands busy
Orcs Must Die!
Active shooting supplements the traps
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fortified
Martian waves are scripted compositions
Orcs Must Die!
Orc waves follow fixed paths
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fortified
Wave makeup is known after a single attempt
Orcs Must Die!
Minor wave composition randomness
Orcs Must Die! leans a little harder on optimization, though the gap is small.
Fortified
Defense placement and hero loadout economy decide rounds
Orcs Must Die!
Trap placement and kill-corridor economics are the game
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.