head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; Scribblenauts Unmasked: A DC Comics Adventure demands more variance.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.

Optimization · Pure Optimization
A creative vocabulary puzzle about conjuring the right object for each prompt.
Portal leans Optimization (Pure Optimization); Scribblenauts Unmasked: A DC Comics Adventure leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Scribblenauts Unmasked: A DC Comics Adventure
Typing words is the only physical act
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Portal
No adversary modeling player.
Scribblenauts Unmasked: A DC Comics Adventure
Puzzles are static prompts, no adversary
Scribblenauts Unmasked: A DC Comics Adventure leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Scribblenauts Unmasked: A DC Comics Adventure
Objectives are visible; little stays hidden
Portal leans clearly harder on optimization.
Portal
Pure puzzle-solving optimization.
Scribblenauts Unmasked: A DC Comics Adventure
Finding clever word-object solutions is the entire test
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.