head to head
vs
Fallout 3vsVolume
Fallout 3 leans Optimization (Pure Optimization); Volume leans Optimization (Pure Optimization).
Fallout 3Volume
Axis by axis
Execution3 vs 2
Fallout 3 leans harder on execution: VATS-leaning combat, low aim demand
Reads1 vs 1
Even - both lean on reads about the same.
Variance2 vs 2
Even - both lean on variance about the same.
Optimization7 vs 8
Volume leans harder on optimization: Distraction sequencing and guard timing puzzles are completely solvable
Two games can score the same on an axis and still test it in very different ways - read each rationale, not just the number.