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
The toned-down crossover fighter matching Mortal Kombat's roster against DC superheroes.
Art of Fighting 2 leans Execution (Competitive PvP); Mortal Kombat vs. DC Universe 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 vs. DC Universe
Juggle combos and klose kombat timing
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 vs. DC Universe
Human mixups, though a simpler toolset than peers
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 vs. DC Universe
Deterministic crossover combat
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 vs. DC Universe
Mapping juggle routes and matchup tools rewards practice
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.