head to head
Portal 2 asks more than Deponia, and the gap is execution.

Optimization · Pure Optimization
A chaotic comedy adventure whose elaborate multi-step puzzles test patience with absurd causal chains.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Deponia leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Deponia
Point-and-click with no timing elements
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.
Deponia
Comedy adventure with scripted characters throughout
Portal 2
No opponent; puzzles are static.
Deponia leans a little harder on variance, though the gap is small.
Deponia
Deterministic puzzle world with fixed solutions
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans a little harder on optimization, though the gap is small.
Deponia
Convoluted Rube Goldberg puzzle chains demand careful causal mapping
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.