head to head
vs
Left 4 DeadvsS.T.A.L.K.E.R.: Shadow of Chernobyl
Left 4 Dead leans Execution (Twitch Chaos); S.T.A.L.K.E.R.: Shadow of Chernobyl leans Optimization (Practiced Mastery).
Left 4 DeadS.T.A.L.K.E.R.: Shadow of Chernobyl
Axis by axis
Execution7 vs 5
Left 4 Dead leans harder on execution: Headshots, melee shoves, and special-infected reaction time
Reads2 vs 1
Left 4 Dead leans harder on reads: Versus mode adds human ambush mindgames
Variance5 vs 5
Even - both lean on variance about the same.
Optimization5 vs 6
S.T.A.L.K.E.R.: Shadow of Chernobyl leans harder on optimization: Artifact economy, routes, and stash knowledge converge
Two games can score the same on an axis and still test it in very different ways - read each rationale, not just the number.