head to head
Garry's Mod asks more than Silent Hill 2, and the gap is reads.

Reads · Light / Casual
Source-engine sandbox whose community modes range from building to social deduction.

Execution · Light / Casual
A psychological survival horror game where atmosphere and puzzle-solving matter more than combat.
Garry's Mod leans Reads (Light / Casual); Silent Hill 2 leans Execution (Light / Casual).
Silent Hill 2 leans a little harder on execution, though the gap is small.
Garry's Mod
Varies by mode; base sandbox is undemanding
Silent Hill 2
clunky combat with modest execution demand
Garry's Mod leans clearly harder on reads.
Garry's Mod
Social deduction modes like TTT involve humans
Silent Hill 2
enemies scripted, not truly adaptive
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Garry's Mod
Hidden roles and player chaos in popular modes
Silent Hill 2
fog and enemy placement randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Garry's Mod
Contraption building rewards systems knowledge
Silent Hill 2
puzzle logic and resource use are solvable
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.