head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Optimization · Pure Optimization
An elegant hex-grid logic puzzler that is always solvable by deduction alone, never guessing.

Optimization · Pure Optimization
A perfect-information tactics puzzle solved one turn at a time.
Hexcells leans Optimization (Pure Optimization); Into the Breach leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Hexcells
Clicking hexes calmly; no physical test.
Into the Breach
No mechanical inputs
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Hexcells
No opponent exists.
Into the Breach
Enemy moves telegraphed fully each turn
Into the Breach leans a little harder on variance, though the gap is small.
Hexcells
Designed to need zero guessing; full information.
Into the Breach
Light spawn and squad randomness
Into the Breach leans a little harder on optimization, though the gap is small.
Hexcells
Minesweeper-style pure deduction is the entire game.
Into the Breach
Pure puzzle - perfect-information chess each turn
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.