head to head
Neither is simply harder - they are hard in different places. Bloons TD 6 demands more optimization; The Elder Scrolls V: Skyrim demands more execution.

Optimization · Pure Optimization
A deep tower defense about popping waves of balloons with monkey towers.

Optimization · Pure Optimization
An open-world RPG mostly about discovering and stacking exploitable progression systems.
Bloons TD 6 leans Optimization (Pure Optimization); The Elder Scrolls V: Skyrim leans Optimization (Pure Optimization).
The Elder Scrolls V: Skyrim leans clearly harder on execution.
Bloons TD 6
Placement clicks only; no dexterity ceiling
The Elder Scrolls V: Skyrim
Combat is forgiving; aim and timing rarely punish you.
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
The Elder Scrolls V: Skyrim
Enemy AI is scripted and exploitable; not adaptive.
The Elder Scrolls V: Skyrim leans a little harder on variance, though the gap is small.
Bloons TD 6
Wave order is deterministic; tiny targeting randomness
The Elder Scrolls V: Skyrim
Loot tables and leveled lists inject mild randomness.
Bloons TD 6 leans clearly harder on optimization.
Bloons TD 6
Tower placement, upgrades, and economy are near-solvable
The Elder Scrolls V: Skyrim
Skill stacking, enchant loops, and exploits are deeply solvable.
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.