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
Peak PS2-era Ratchet, blending arsenal progression with polished combat arenas.

Optimization · Practiced Mastery
A mining metroidvania about digging efficient tunnels, hauling ore, and compounding upgrades.
Ratchet & Clank: Up Your Arsenal leans Optimization (Practiced Mastery); SteamWorld Dig 2 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.
Ratchet & Clank: Up Your Arsenal
Faster combat demanding strafing and aim precision.
SteamWorld Dig 2
Light platforming and digging dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Ratchet & Clank: Up Your Arsenal
Campaign is scripted; legacy multiplayer added a thin PvP layer.
SteamWorld Dig 2
Scripted enemies only
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Ratchet & Clank: Up Your Arsenal
Unknown encounters only on first playthrough.
SteamWorld Dig 2
Procedural ore pockets add mild run-to-run unknowns
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Ratchet & Clank: Up Your Arsenal
Weapon XP, bolt economy, and route mastery decide everything.
SteamWorld Dig 2
Dig routing, resource economy, and upgrade ordering are the 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.