head to head
FIFA Soccer 11 asks more than Agar.io, and the gap is execution.

Reads · Competitive PvP
A browser arena where your cell eats smaller players and flees bigger ones.

Execution · Competitive PvP
Football sim testing stick execution and reading a human opponent's tactical habits.
Agar.io leans Reads (Competitive PvP); FIFA Soccer 11 leans Execution (Competitive PvP).
FIFA Soccer 11 leans clearly harder on execution.
Agar.io
Mouse steering and split timing
FIFA Soccer 11
Pass timing, dribbling and finishing demand stick skill
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Agar.io
Baiting and predicting human blobs decides fights
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.
Agar.io
Spawn locations and lobby makeup random
FIFA Soccer 11
Deflections and keeper behaviour add bounded chaos
FIFA Soccer 11 leans a little harder on optimization, though the gap is small.
Agar.io
Split-merge math is shallow but real
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.