head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; Spaceland: Sci-Fi Indie Tactics demands more variance.

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

Optimization · Pure Optimization
A turn-based tactics game testing positioning and squad optimization against aliens.
Portal leans Optimization (Pure Optimization); Spaceland: Sci-Fi Indie Tactics leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Spaceland: Sci-Fi Indie Tactics
Turn-based commands need no twitch input
Spaceland: Sci-Fi Indie Tactics leans clearly harder on reads.
Portal
No adversary modeling player.
Spaceland: Sci-Fi Indie Tactics
Alien enemies follow scripted AI, not adapting to you
Spaceland: Sci-Fi Indie Tactics leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Spaceland: Sci-Fi Indie Tactics
Hit chances and fog of war add measured randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Portal
Pure puzzle-solving optimization.
Spaceland: Sci-Fi Indie Tactics
Positioning, ability use and squad planning win 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.