head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; Sunrider: Liberation Day demands more variance.

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

Optimization · Pure Optimization
A turn-based tactics visual novel testing target priority and ability management.
Portal leans Optimization (Pure Optimization); Sunrider: Liberation Day leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Sunrider: Liberation Day
Menu-driven attacks, no twitch element
Sunrider: Liberation Day leans clearly harder on reads.
Portal
No adversary modeling player.
Sunrider: Liberation Day
Enemy AI is scripted, not adaptive prediction
Sunrider: Liberation Day leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Sunrider: Liberation Day
Hit and accuracy rolls add measured randomness
Portal leans a little harder on optimization, though the gap is small.
Portal
Pure puzzle-solving optimization.
Sunrider: Liberation Day
Targeting priority and resource management decides battles
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.