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
A third-person tower defense about funneling orc hordes into gleefully lethal trap corridors.

Optimization · Pure Optimization
A tower-defense game about placing traps along paths to protect baby monsters.
Orcs Must Die! leans Optimization (Pure Optimization); PixelJunk Monsters 2 leans Optimization (Pure Optimization).
Orcs Must Die! leans a little harder on execution, though the gap is small.
Orcs Must Die!
Active shooting supplements the traps
PixelJunk Monsters 2
Some real-time placement timing under wave pressure.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Orcs Must Die!
Orc waves follow fixed paths
PixelJunk Monsters 2
Enemy waves are scripted, not adaptive.
PixelJunk Monsters 2 leans a little harder on variance, though the gap is small.
Orcs Must Die!
Minor wave composition randomness
PixelJunk Monsters 2
Wave composition adds some unpredictability.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Orcs Must Die!
Trap placement and kill-corridor economics are the game
PixelJunk Monsters 2
Tower placement and upgrade paths are deeply solvable.
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.