head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Practiced Mastery
Family-friendly dungeon crawler that swaps Minecraft's building for loot and hack-and-slash.

Optimization · Practiced Mastery
Routing efficient digs and upgrades through a randomised mine.
Minecraft Dungeons leans Optimization (Practiced Mastery); SteamWorld Dig leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Minecraft Dungeons
Dodge-rolls and kiting through mob swarms
SteamWorld Dig
Digging and platforming need modest precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Minecraft Dungeons
Enemies are scripted hordes
SteamWorld Dig
Enemies follow simple fixed patterns
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Minecraft Dungeons
Random loot and enchantment rolls drive power
SteamWorld Dig
Randomised mine layouts hide ore and hazards each run
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Minecraft Dungeons
Gear synergies and enchant builds carry difficulty
SteamWorld Dig
Upgrade routing and efficient dig paths drive progress
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.