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 factory-engineering sandbox about scaling throughput against your own bottlenecks.

Optimization · Pure Optimization
A tower-defense game about building optimal mazes and tower combinations.
Factorio leans Optimization (Pure Optimization); Super Sanctum TD 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.
Factorio
Some APM in early hand-crafting; otherwise irrelevant.
Super Sanctum TD
Placing towers needs no twitch; abilities are light
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Factorio
Biters follow fixed pollution rules; no adaptive opponent.
Super Sanctum TD
Enemy waves are scripted, not adaptive minds
Super Sanctum TD leans a little harder on variance, though the gap is small.
Factorio
Resource patch placement adds minor map randomness.
Super Sanctum TD
Wave composition is predictable once learned
Factorio leans a little harder on optimization, though the gap is small.
Factorio
Throughput, ratios, and logistics are the entire game.
Super Sanctum TD
Maze design and tower synergy are the entire 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.