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.

Variance · Systems & Chaos
Turn-based resource management through randomly generated dungeon layouts.

Variance · Systems & Chaos
A gothic exploration roguelike about sailing an underground ocean, trading terror for stories and profit.
Pokémon Mystery Dungeon: Red Rescue Team leans Variance (Systems & Chaos); Sunless Sea leans Variance (Systems & Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Pokémon Mystery Dungeon: Red Rescue Team
Turn-based grid movement - no twitch demands
Sunless Sea
Slow boat combat barely tests the hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Pokémon Mystery Dungeon: Red Rescue Team
Wild Pokémon follow simple deterministic AI
Sunless Sea
Horrors are scripted or random, never adaptive
Sunless Sea leans a little harder on variance, though the gap is small.
Pokémon Mystery Dungeon: Red Rescue Team
Random dungeon layouts, items and encounters each run
Sunless Sea
Hidden map, random events and unknown story branches dominate
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Pokémon Mystery Dungeon: Red Rescue Team
Team building, item management and type matchups carry runs
Sunless Sea
Trade routes and fuel math converge once mapped
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.