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
Early fighting-game execution and spacing, plus mind-games against humans.

Execution · Competitive PvP
Fighting-game execution and opponent prediction across an enormous, loosely balanced roster.
Art of Fighting 2 leans Execution (Competitive PvP); Mortal Kombat: Armageddon leans Execution (Competitive PvP).
Art of Fighting 2 leans a little harder on execution, though the gap is small.
Art of Fighting 2
Spirit-gauge specials and spacing demand drilled precision
Mortal Kombat: Armageddon
Combo strings and kombat timing decide exchanges
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Art of Fighting 2
Human matches turn on baiting and conditioning
Mortal Kombat: Armageddon
Versus humans, baiting and punishing habits is the meta
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Art of Fighting 2
Nothing random in the fixed roster
Mortal Kombat: Armageddon
No hidden information once movesets are known
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Art of Fighting 2
Notoriously hard AI patterns are studyable scripts, not minds
Mortal Kombat: Armageddon
A 62-character roster of matchup knowledge to internalise
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.