head to head
vs
Half-Life 2vsKillzone
Half-Life 2 leans Execution (Pure Mechanics); Killzone leans Execution (Practiced Mastery).
Half-Life 2Killzone
Axis by axis
Execution6 vs 6
Even - both lean on execution about the same.
Reads1 vs 2
Killzone leans harder on reads: Campaign Helghast follow scripts; servers are long dead
Variance1 vs 1
Even - both lean on variance about the same.
Optimization3 vs 4
Killzone leans harder on optimization: Character choice and route knowledge solve each level
Two games can score the same on an axis and still test it in very different ways - read each rationale, not just the number.