head to head
Fallout: New Vegas asks more than Zoo Tycoon 2, and the gap is execution.

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

Optimization · Pure Optimization
The 3D zoo-building sequel with first-person park strolling and deeper animal care.
Fallout: New Vegas leans Optimization (Pure Optimization); Zoo Tycoon 2 leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
Zoo Tycoon 2
Pure point-and-click construction
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
Zoo Tycoon 2
Nothing adapts to you
Fallout: New Vegas leans a little harder on variance, though the gap is small.
Fallout: New Vegas
Some loot and crit RNG
Zoo Tycoon 2
Biome needs fully documented and stable
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Zoo Tycoon 2
Exhibit design, economy, and animal care optimisation
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.