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 deep tower defense about popping waves of balloons with monkey towers.

Optimization · Pure Optimization
A sliding-block puzzle about deducing the right merge sequence per board.
Bloons TD 6 leans Optimization (Pure Optimization); Denki Blocks! 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.
Bloons TD 6
Placement clicks only; no dexterity ceiling
Denki Blocks!
Sliding blocks has no timing or twitch demand
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Bloons TD 6
Bloon waves are fixed and known
Denki Blocks!
Solo puzzle with no opponent to predict
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Bloons TD 6
Wave order is deterministic; tiny targeting randomness
Denki Blocks!
Each puzzle is fixed, nothing random to map
Bloons TD 6 leans a little harder on optimization, though the gap is small.
Bloons TD 6
Tower placement, upgrades, and economy are near-solvable
Denki Blocks!
Solving the block-merging sequence 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.