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

Optimization · Pure Optimization
A flash puzzle about rolling a rectangular block into the hole without falling off.

Optimization · Pure Optimization
Short free sokoban puzzler about assembling a harem of sharply dressed demon girls.
Bloxorz leans Optimization (Pure Optimization); Helltaker 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.
Bloxorz
Deliberate moves; no time pressure.
Helltaker
One bullet-dodge finale aside, no dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Bloxorz
No opponent at all.
Helltaker
No opponent
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Bloxorz
Levels are fixed and fully visible.
Helltaker
Fully deterministic puzzles
Bloxorz leans a little harder on optimization, though the gap is small.
Bloxorz
Each level is a literally solvable move puzzle.
Helltaker
Each sokoban level has an exact move solution
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.