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

Execution · Competitive PvP
Hardcore team shooter where one bullet kills and the HUD tells you nothing.

Execution · Pure Mechanics
A fast, low-fi browser FPS built around twitch aim and movement skill.
Insurgency leans Execution (Competitive PvP); Krunker leans Execution (Pure Mechanics).
Krunker leans a little harder on execution, though the gap is small.
Insurgency
One-shot lethality rewards precise aim
Krunker
fast twitch aim and movement in browser FPS
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Insurgency
Human squads flank and adapt each round
Krunker
reading human opponents' positioning and peeks
Insurgency leans a little harder on variance, though the gap is small.
Insurgency
No killcam or HUD hides enemy positions
Krunker
minor spawn and loadout randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Insurgency
Loadout points and objective route knowledge
Krunker
class loadouts and map knowledge are learnable
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.