head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Pure Mechanics
An endless arcade runner testing reflexes against scrolling hazards.

Execution · Practiced Mastery
The infamous, glitch-ridden 2006 Sonic reboot where the physics are the real boss.
Nyan Cat: Lost In Space leans Execution (Pure Mechanics); Sonic the Hedgehog (2006) leans Execution (Practiced Mastery).
Nyan Cat: Lost In Space leans a little harder on execution, though the gap is small.
Nyan Cat: Lost In Space
Precise dodging and platform timing decides survival
Sonic the Hedgehog (2006)
Fighting unreliable physics demands constant correction
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Nyan Cat: Lost In Space
No opponent to predict; scripted hazards
Sonic the Hedgehog (2006)
No adaptive opposition
Nyan Cat: Lost In Space leans a little harder on variance, though the gap is small.
Nyan Cat: Lost In Space
Procedural obstacle layouts add some unpredictability
Sonic the Hedgehog (2006)
Bugs make outcomes partly unpredictable
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Nyan Cat: Lost In Space
Upgrade choices and route knowledge improve runs
Sonic the Hedgehog (2006)
Learning which routes the jank permits
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.