head to head
Super Smash Bros. Melee asks more than Under Night In-Birth II Sys:Celes, and the gap is execution.

Execution · Competitive PvP
A platform fighter with one of the highest execution ceilings in any competitive game, layered on top of deep human reads.

Reads · Grand Arena
A neutral-focused fighter where managing the GRD gauge against an adapting opponent creates a constant strategic tug-of-war.
Super Smash Bros. Melee leans Execution (Competitive PvP); Under Night In-Birth II Sys:Celes leans Reads (Grand Arena).
Super Smash Bros. Melee leans clearly harder on execution.
Super Smash Bros. Melee
Wavedashing, L-cancels, and tech-chasing set an extreme physical ceiling
Under Night In-Birth II Sys:Celes
GRD-boosted combos and precise Chain Shift timing demand real execution
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Super Smash Bros. Melee
Reading DI choices and opponent adaptive habits is constant and non-convergent
Under Night In-Birth II Sys:Celes
GRD tug-of-war with a human opponent is persistently adaptive
Super Smash Bros. Melee leans a little harder on variance, though the gap is small.
Super Smash Bros. Melee
Stage hazard RNG and spawn positions add marginal chaos
Under Night In-Birth II Sys:Celes
No RNG; GRD state is visible information
Under Night In-Birth II Sys:Celes leans a little harder on optimization, though the gap is small.
Super Smash Bros. Melee
Character matchup tiers and optimal movement routing are deeply studied
Under Night In-Birth II Sys:Celes
GRD management theory and optimal punish routing are well-documented
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.