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 · Pure Optimization
Comedic point-and-click adventure of Guybrush Threepwood, hand-drawn at its peak.

Optimization · Systems & Chaos
A zany LucasArts adventure where a tabloid reporter foils aliens dumbing down humanity with a 60-Hz hum.
The Curse of Monkey Island leans Optimization (Pure Optimization); Zak McKracken and the Alien Mindbenders leans Optimization (Systems & Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
The Curse of Monkey Island
pointing and clicking only
Zak McKracken and the Alien Mindbenders
Verb-and-click interface; nothing physical.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
The Curse of Monkey Island
no adaptive opponent
Zak McKracken and the Alien Mindbenders
Dumb aliens run on rails; no adaptation anywhere.
Zak McKracken and the Alien Mindbenders leans a little harder on variance, though the gap is small.
The Curse of Monkey Island
puzzle solutions unknown on first play, then fixed
Zak McKracken and the Alien Mindbenders
Globe-trotting item requirements are obscure on first play.
The Curse of Monkey Island leans a little harder on optimization, though the gap is small.
The Curse of Monkey Island
inventory logic puzzles are fully solvable
Zak McKracken and the Alien Mindbenders
Multi-character inventory chains form one big solvable 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.