head to head
Super Smash Bros. Melee asks more than Halo 2: Anniversary, and the gap is execution.

Execution · Competitive PvP
Tests arena-shooter aim and map-control prediction against human lobbies.

Execution · Competitive PvP
A platform fighter with one of the highest execution ceilings in any competitive game, layered on top of deep human reads.
Halo 2: Anniversary leans Execution (Competitive PvP); Super Smash Bros. Melee leans Execution (Competitive PvP).
Super Smash Bros. Melee leans clearly harder on execution.
Halo 2: Anniversary
Aim, grenades and movement decide every multiplayer duel
Super Smash Bros. Melee
Wavedashing, L-cancels, and tech-chasing set an extreme physical ceiling
Super Smash Bros. Melee leans clearly harder on reads.
Halo 2: Anniversary
Predicting human positioning and power-weapon pushes is constant
Super Smash Bros. Melee
Reading DI choices and opponent adaptive habits is constant and non-convergent
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Halo 2: Anniversary
Static spawns and timers leave little true randomness
Super Smash Bros. Melee
Stage hazard RNG and spawn positions add marginal chaos
Super Smash Bros. Melee leans a little harder on optimization, though the gap is small.
Halo 2: Anniversary
Weapon timers, map control and campaign routes are learnable systems
Super Smash Bros. Melee
Character matchup tiers and optimal movement routing are deeply studied
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.