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.

Execution · Practiced Mastery
Straightforward cover-shooting aim against fully scripted enemy waves.

Execution · Practiced Mastery
A retro-Soviet action shooter mixing gunplay with light upgrade strategy.
Army of Two: The Devil's Cartel leans Execution (Practiced Mastery); Atomic Heart leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Army of Two: The Devil's Cartel
Cover shooting rewards decent aim, nothing more
Atomic Heart
Shooting and dodging carry the combat.
Atomic Heart leans a little harder on reads, though the gap is small.
Army of Two: The Devil's Cartel
Cartel enemies follow scripted cover AI
Atomic Heart
Robot enemies follow scripted patterns.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Army of Two: The Devil's Cartel
Encounters replay identically
Atomic Heart
Encounters largely fixed.
Atomic Heart leans a little harder on optimization, though the gap is small.
Army of Two: The Devil's Cartel
Weapon customization adds light loadout math
Atomic Heart
Upgrades and weapon crafting 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.