head to head
Heat SignaturevsXCOM: Enemy Unknown
Heat Signature leans Variance (Systems & Chaos); XCOM: Enemy Unknown leans Optimization (Systems & Chaos).
Heat SignatureXCOM: Enemy Unknown
Axis by axis
Execution3 vs 3
Even - both lean on execution about the same.
Reads0 vs 1
XCOM: Enemy Unknown leans harder on reads: Aliens follow scripted AI, never model your specific habits
Variance7 vs 7
Even - both lean on variance about the same.
Optimization7 vs 8
XCOM: Enemy Unknown leans harder on optimization: Squad composition, research order, and base economy are 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.

