head to head
Overwatch asks more than Insurgency: Sandstorm, and the gap is optimization.

Execution · Competitive PvP
Hardcore tactical shooter with lethal TTK.

Execution · Grand Arena
Team hero shooter blending FPS mechanics with ability economy mind games.
Insurgency: Sandstorm leans Execution (Competitive PvP); Overwatch leans Execution (Grand Arena).
Insurgency: Sandstorm leans a little harder on execution, though the gap is small.
Insurgency: Sandstorm
One-shot kills demand pixel-perfect aim
Overwatch
Hero aim, movement, and ability timing
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Insurgency: Sandstorm
Holding angles and pushes are mind games
Overwatch
Ult tracking, flanks, and baiting human teams
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Insurgency: Sandstorm
Very low RNG, near pure skill
Overwatch
Minor spread and matchmaking noise
Overwatch leans clearly harder on optimization.
Insurgency: Sandstorm
Loadout points and class roles tuned
Overwatch
Team comps, ult economy, and positioning theory
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.