head to head
Neither is simply harder - they are hard in different places. Portal 2 demands more execution; Transport Tycoon Deluxe demands more variance.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.

Optimization · Pure Optimization
The definitive transport network sim where perfect rail signaling and routing is the whole game.
Portal 2 leans Optimization (Pure Optimization); Transport Tycoon Deluxe leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Portal 2
Portal placement requires some precision but timing is lenient.
Transport Tycoon Deluxe
Pausable map clicking, no dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Portal 2
No opponent; puzzles are static.
Transport Tycoon Deluxe
AI competitors follow simple mappable logic
Transport Tycoon Deluxe leans clearly harder on variance.
Portal 2
Puzzles are deterministic with no randomness.
Transport Tycoon Deluxe
Industry placement and economy events add slight noise
Transport Tycoon Deluxe leans a little harder on optimization, though the gap is small.
Portal 2
Solving the puzzle's logic IS the entire game.
Transport Tycoon Deluxe
Signal logic and network throughput are literally an engineering problem
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.