head to head
Sniper Elite III asks more than Manhunt, and the gap is execution.

Optimization · Practiced Mastery
Grim stealth horror about luring scripted hunters into executions.

Execution · Practiced Mastery
Plannable stealth routing punctuated by precise ballistic marksmanship.
Manhunt leans Optimization (Practiced Mastery); Sniper Elite III leans Execution (Practiced Mastery).
Sniper Elite III leans clearly harder on execution.
Manhunt
Stealth timing on executions
Sniper Elite III
Ballistic long shots demand steady, compensated aim
Sniper Elite III leans a little harder on reads, though the gap is small.
Manhunt
Hunters patrol on scripts
Sniper Elite III
Enemy AI follows mappable alert and search routines
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Manhunt
Patrol noise reactions add small unpredictability
Sniper Elite III
Patrol details and wind vary slightly per attempt
Sniper Elite III leans a little harder on optimization, though the gap is small.
Manhunt
Shadow routes and lure tactics are learnable
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.