head to head
DOOM (2016) asks more than Rhythm Heaven Megamix, and the gap is optimization.

Execution · Pure Mechanics
Push-forward arena FPS where movement and aim are the whole game.

Execution · Pure Mechanics
Pure rhythmic timing against fixed musical cues, minigame after minigame.
DOOM (2016) leans Execution (Pure Mechanics); Rhythm Heaven Megamix leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
DOOM (2016)
Aim, movement, glory-kill timing all peak.
Rhythm Heaven Megamix
Beat-perfect input timing is the entire test
DOOM (2016) leans a little harder on reads, though the gap is small.
DOOM (2016)
Demons scripted attack patterns.
Rhythm Heaven Megamix
No opponent - only the music
DOOM (2016) leans a little harder on variance, though the gap is small.
DOOM (2016)
Minimal encounter randomness.
Rhythm Heaven Megamix
Every minigame plays identically each attempt
DOOM (2016) leans clearly harder on optimization.
DOOM (2016)
Rune and weapon mod picks meaningful.
Rhythm Heaven Megamix
Cues are learned quickly; timing remains the wall
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.