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

Execution · Practiced Mastery
A Pac-Man-style routing and dodging test wearing an Alien license.

Execution · Practiced Mastery
Arcade-style western shooter built around stage gunfights and showdown duels.
Alien leans Execution (Practiced Mastery); Red Dead Revolver leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Alien
Maze dodging under drone pursuit is pure timing
Red Dead Revolver
Arcade gunplay and duel timing dominate
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Alien
Drones chase with simple fixed logic, nothing adaptive
Red Dead Revolver
Enemies are scripted shooting-gallery foes
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Alien
Drone movements vary slightly per attempt
Red Dead Revolver
Minor spawn variation
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Alien
Optimal egg-clearing routes are quickly mappable, Pac-Man style
Red Dead Revolver
Level layouts and duel rhythms 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.