head to head
Portal 2 asks more than Denki Blocks!, and the gap is execution.

Optimization · Pure Optimization
A sliding-block puzzle about deducing the right merge sequence per board.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Denki Blocks! leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Denki Blocks!
Sliding blocks has no timing or twitch demand
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.
Denki Blocks!
Solo puzzle with no opponent to predict
Portal 2
No opponent; puzzles are static.
Denki Blocks! leans a little harder on variance, though the gap is small.
Denki Blocks!
Each puzzle is fixed, nothing random to map
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans a little harder on optimization, though the gap is small.
Denki Blocks!
Solving the block-merging sequence is the entire game
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.