head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, 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
Side-on turn-based tactics where you manually aim ricocheting bullets for a steambot pirate crew.
Orcs Must Die! leans Optimization (Pure Optimization); SteamWorld Heist leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Orcs Must Die!
Active shooting supplements the traps
SteamWorld Heist
Manual aim and ricochet shots reward steady hands
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
SteamWorld Heist
Enemy bots follow fixed behaviors
SteamWorld Heist leans a little harder on variance, though the gap is small.
Orcs Must Die!
Minor wave composition randomness
SteamWorld Heist
Procedural ship layouts and loot drops
Orcs Must Die! leans a little harder on optimization, though the gap is small.
Orcs Must Die!
Trap placement and kill-corridor economics are the game
SteamWorld Heist
Crew builds, weapon picks, and turn routing carry runs
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.