head to head
Neither is simply harder - they are hard in different places. Brawlhalla demands more reads; Call of Duty: Modern Warfare 2 demands more variance.

Execution · Competitive PvP
A platform fighter built on tight inputs and dodge-read mind games.

Execution · Competitive PvP
Blockbuster 2009 sequel famous for killstreak chains and frantic multiplayer.
Brawlhalla leans Execution (Competitive PvP); Call of Duty: Modern Warfare 2 leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Brawlhalla
Frame-tight inputs and recoveries decide stocks.
Call of Duty: Modern Warfare 2
Fast time-to-kill rewards raw aim and reflex
Brawlhalla leans clearly harder on reads.
Brawlhalla
Adaptive opponents bait dodges and reads constantly.
Call of Duty: Modern Warfare 2
Outguessing human rotations and flanks
Call of Duty: Modern Warfare 2 leans clearly harder on variance.
Brawlhalla
Weapon spawns add minor randomness.
Call of Duty: Modern Warfare 2
Spawn flips and killstreak randomness
Call of Duty: Modern Warfare 2 leans a little harder on optimization, though the gap is small.
Brawlhalla
Matchup knowledge and stage control are learnable.
Call of Duty: Modern Warfare 2
Killstreak economy, loadout and map knowledge
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.