head to head
Neither is simply harder - they are hard in different places. Danganronpa: Trigger Happy Havoc demands more variance; Portal 2 demands more optimization.

Optimization · Pure Optimization
A school murder mystery where class trials test players' ability to assemble evidence into the correct counter-argument.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Danganronpa: Trigger Happy Havoc leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Danganronpa: Trigger Happy Havoc
Class trial rhythm sections add minor timing layer
Portal 2
Portal placement requires some precision but timing is lenient.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Danganronpa: Trigger Happy Havoc
Blackened is scripted per chapter; no adaptive deduction opponent
Portal 2
No opponent; puzzles are static.
Danganronpa: Trigger Happy Havoc leans clearly harder on variance.
Danganronpa: Trigger Happy Havoc
Hidden killer identities and evidence drive trial uncertainty
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans clearly harder on optimization.
Danganronpa: Trigger Happy Havoc
Gathering evidence and building the correct argument chain is a solvable deduction loop
Portal 2
Solving the puzzle's logic IS the entire game.
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.