head to head
Sniper Elite III asks more than Metal Gear Solid 2: Substance, and the gap is execution.

Optimization · Practiced Mastery
A stealth-action game where planning routes past scripted guards is the deep skill.

Execution · Practiced Mastery
Plannable stealth routing punctuated by precise ballistic marksmanship.
Metal Gear Solid 2: Substance leans Optimization (Practiced Mastery); Sniper Elite III leans Execution (Practiced Mastery).
Sniper Elite III leans clearly harder on execution.
Metal Gear Solid 2: Substance
stealth timing and aim matter
Sniper Elite III
Ballistic long shots demand steady, compensated aim
Sniper Elite III leans a little harder on reads, though the gap is small.
Metal Gear Solid 2: Substance
guards are scripted, no adaptation
Sniper Elite III
Enemy AI follows mappable alert and search routines
Sniper Elite III leans a little harder on variance, though the gap is small.
Metal Gear Solid 2: Substance
minor patrol randomness
Sniper Elite III
Patrol details and wind vary slightly per attempt
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Metal Gear Solid 2: Substance
stealth routes and gadgets solvable
Sniper Elite III
Open maps reward planned routes, sound masking and relocation
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.