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 · Practiced Mastery
A cinematic open-world western leaning on shooting feel and atmosphere.

Execution · Practiced Mastery
A cartoonish horde shooter sequel of planet-hopping monster massacres.
Red Dead Redemption 2 leans Execution (Practiced Mastery); Serious Sam 2 leans Execution (Practiced Mastery).
Serious Sam 2 leans a little harder on execution, though the gap is small.
Red Dead Redemption 2
Gunplay and Dead Eye reward aim and timing.
Serious Sam 2
Sustained horde-clearing aim and strafing
Red Dead Redemption 2 leans a little harder on reads, though the gap is small.
Red Dead Redemption 2
Enemies use scripted AI patterns, not adaptation.
Serious Sam 2
Enemy waves are entirely scripted
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Red Dead Redemption 2
Some hunting and weather randomness, lightly hidden.
Serious Sam 2
Cartoon set-pieces surprise once
Serious Sam 2 leans a little harder on optimization, though the gap is small.
Red Dead Redemption 2
Loadouts and routes solvable but loose.
Serious Sam 2
Target priority and arena routes 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.