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
Vietnam-era large-scale multiplayer shooter mixing infantry firefights with helicopters and jungle ambushes.

Execution · Competitive PvP
Football sim testing stick execution and reading a human opponent's tactical habits.
Battlefield Vietnam leans Execution (Competitive PvP); FIFA Soccer 11 leans Execution (Competitive PvP).
Battlefield Vietnam leans a little harder on execution, though the gap is small.
Battlefield Vietnam
Gunplay, vehicle handling, and helicopter piloting
FIFA Soccer 11
Pass timing, dribbling and finishing demand stick skill
FIFA Soccer 11 leans a little harder on reads, though the gap is small.
Battlefield Vietnam
Human squads flank and contest objectives unpredictably
FIFA Soccer 11
Human opponents' defensive habits and attacking patterns must be modelled
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Battlefield Vietnam
Spawn waves and vehicle availability shuffle fights
FIFA Soccer 11
Deflections and keeper behaviour add bounded chaos
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Battlefield Vietnam
Map control, loadouts, and ticket-bleed knowledge
FIFA Soccer 11
Formations, tactics and squad knowledge shape matches
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.