head to head
Divinity: Original Sin 2vsUnderrail
Divinity: Original Sin 2 leans Optimization (Pure Optimization); Underrail leans Optimization (Pure Optimization).
Divinity: Original Sin 2Underrail
Axis by axis
Execution2 vs 3
Underrail leans harder on execution: Real-time combat phases require some positioning and grenade timing
Reads2 vs 1
Divinity: Original Sin 2 leans harder on reads: Multiplayer PvP arena adds light opponent-reading; solo is scripted
Variance5 vs 5
Even - both lean on variance about the same.
Optimization10 vs 10
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.

