head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Pure Mechanics
An asymmetric horror FPS letting you play marine, alien, or predator, each with wholly different abilities.

Execution · Pure Mechanics
An asymmetric FPS with three interlocking campaigns as marine, alien, and predator on the same colony.
Aliens versus Predator (1999) leans Execution (Pure Mechanics); Aliens vs. Predator 2 leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Aliens versus Predator (1999)
Fast aliens and panicked aim demand twitch reflexes
Aliens vs. Predator 2
Wall-crawling aliens and panicked marines test raw aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Aliens versus Predator (1999)
Asymmetric multiplayer pits unlike species against each other
Aliens vs. Predator 2
Cross-species multiplayer rewards outguessing human opponents
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Aliens versus Predator (1999)
Motion-tracker dread and dark vents hide enemy positions
Aliens vs. Predator 2
Motion tracker pings and dark corridors conceal threats
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Aliens versus Predator (1999)
Mastering each species' tools and level knowledge
Aliens vs. Predator 2
Species matchup knowledge and map control are learnable
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.