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.

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

Optimization · Pure Optimization
Lateral-thinking puzzle solving that converges to a walkthrough once solutions are known.
Downfall leans Optimization (Systems & Chaos); The Secret of Monkey Island: Special Edition leans Optimization (Pure Optimization).
Downfall leans a little harder on execution, though the gap is small.
Downfall
Clicking through scenes has no motor demand
The Secret of Monkey Island: Special Edition
Pointing and clicking has no physical ceiling
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
The Secret of Monkey Island: Special Edition
Insult swordfighting is scripted dialogue lookup, not prediction
Downfall leans a little harder on variance, though the gap is small.
Downfall
Branching horrors are hidden until choices reveal them
The Secret of Monkey Island: Special Edition
Puzzle solutions are hidden information until discovered
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
The Secret of Monkey Island: Special Edition
Once solutions are known the game is fully solved
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.