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

Reads · Mind & Math
A team airship battler testing crew coordination and outmaneuvering human captains.

Reads · Mind & Math
Objective-driven MOBA with shared team XP.
Guns of Icarus Online leans Reads (Mind & Math); Heroes of the Storm leans Reads (Mind & Math).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Guns of Icarus Online
Gunnery arcs and repair juggling need competent hands
Heroes of the Storm
Skillshots and rotations require hands
Heroes of the Storm leans a little harder on reads, though the gap is small.
Guns of Icarus Online
Human captains feint, reposition and counter your ship tactics
Heroes of the Storm
Team-fight cooldown trading is prediction
Heroes of the Storm leans a little harder on variance, though the gap is small.
Guns of Icarus Online
Cloud cover hides ships briefly, little else random
Heroes of the Storm
Map objectives and merc camps vary
Heroes of the Storm leans a little harder on optimization, though the gap is small.
Guns of Icarus Online
Loadouts, role coordination and positioning are deeply plannable
Heroes of the Storm
Talent picks and team comps deep
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.