head to head
Neither is simply harder - they are hard in different places. Fallout: New Vegas demands more execution; The Battle Cats demands more variance.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.

Optimization · Pure Optimization
Lineup optimisation and deploy timing against fixed stages, gated by gacha luck.
Fallout: New Vegas leans Optimization (Pure Optimization); The Battle Cats leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
The Battle Cats
Tapping deploy buttons with timing, minimal dexterity
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
The Battle Cats
Enemy waves are fixed per stage
The Battle Cats leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
The Battle Cats
Gacha rolls gate which cats you even own
Fallout: New Vegas leans a little harder on optimization, though the gap is small.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
The Battle Cats
Lineup building and deploy timing solve each stage
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.