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 · Systems & Chaos
A grim point-and-click testing puzzle persistence through a fixed descent into madness.

Optimization · Pure Optimization
Experimenting with whimsical screens until their hidden interaction logic clicks.
Downfall leans Optimization (Systems & Chaos); Samorost 2 leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Downfall
Clicking through scenes has no motor demand
Samorost 2
Pointing and clicking has no dexterity component
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Downfall
Characters are scripted psyches, not adapting opponents
Samorost 2
No opponent of any kind exists
Downfall leans a little harder on variance, though the gap is small.
Downfall
Branching horrors are hidden until choices reveal them
Samorost 2
Surreal puzzle logic is hidden until experimented with
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Downfall
Puzzle chains and ending routes have fixed solutions
Samorost 2
Each screen is a small solvable interaction puzzle
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.