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 · Practiced Mastery
A block-stacking puzzle about building paths to collect items.

Optimization · Practiced Mastery
Routing efficient digs and upgrades through a randomised mine.
Hello Kitty's Cube Frenzy 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.
Hello Kitty's Cube Frenzy
Block placement timing needs light dexterity
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.
Hello Kitty's Cube Frenzy
Solo with no opponent to predict
SteamWorld Dig
Enemies follow simple fixed patterns
SteamWorld Dig leans a little harder on variance, though the gap is small.
Hello Kitty's Cube Frenzy
Falling block colors add some randomness
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.
Hello Kitty's Cube Frenzy
Planning staircases and color matches solves levels
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.