head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

Execution · Practiced Mastery
A handheld Ratchet & Clank adventure shrunk down for PSP with armour collecting.

Execution · Practiced Mastery
A cinematic open-world western leaning on shooting feel and atmosphere.
Ratchet & Clank: Size Matters leans Execution (Practiced Mastery); Red Dead Redemption 2 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.
Ratchet & Clank: Size Matters
Run-and-gun platforming on PSP controls
Red Dead Redemption 2
Gunplay and Dead Eye reward aim and timing.
Red Dead Redemption 2 leans a little harder on reads, though the gap is small.
Ratchet & Clank: Size Matters
Enemies are scripted
Red Dead Redemption 2
Enemies use scripted AI patterns, not adaptation.
Red Dead Redemption 2 leans a little harder on variance, though the gap is small.
Ratchet & Clank: Size Matters
Fixed levels and drops
Red Dead Redemption 2
Some hunting and weather randomness, lightly hidden.
Ratchet & Clank: Size Matters leans a little harder on optimization, though the gap is small.
Ratchet & Clank: Size Matters
Weapon upgrades and armour-set collecting
Red Dead Redemption 2
Loadouts and routes solvable but loose.
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.