head to head
vs
Call of Duty: Modern Warfare 3vsHalf-Life Deathmatch: Source
Call of Duty: Modern Warfare 3 leans Execution (Pure Mechanics); Half-Life Deathmatch: Source leans Execution (Pure Mechanics).
Call of Duty: Modern Warfare 3Half-Life Deathmatch: Source
Axis by axis
Execution9 vs 8
Call of Duty: Modern Warfare 3 leans harder on execution: aim and reflexes decide most engagements
Reads6 vs 4
Call of Duty: Modern Warfare 3 leans harder on reads: predicting human opponent positioning and habits
Variance2 vs 1
Call of Duty: Modern Warfare 3 leans harder on variance: spawn placement and loadout drops vary
Optimization4 vs 4
Even - both lean on optimization about the same.
Two games can score the same on an axis and still test it in very different ways - read each rationale, not just the number.