head to head
Neither is simply harder - they are hard in different places. DOOM (2016) demands more optimization; Kirby's Pinball Land demands more variance.

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

Execution · Pure Mechanics
Flipper timing against bouncy physics across three fixed tables.
DOOM (2016) leans Execution (Pure Mechanics); Kirby's Pinball Land leans Execution (Pure Mechanics).
DOOM (2016) leans a little harder on execution, though the gap is small.
DOOM (2016)
Aim, movement, glory-kill timing all peak.
Kirby's Pinball Land
Flipper timing and aim control everything the ball does
DOOM (2016) leans a little harder on reads, though the gap is small.
DOOM (2016)
Demons scripted attack patterns.
Kirby's Pinball Land
Tables and bosses are scripted machines
Kirby's Pinball Land leans clearly harder on variance.
DOOM (2016)
Minimal encounter randomness.
Kirby's Pinball Land
Bounce physics keep outcomes partly unpredictable
DOOM (2016) leans clearly harder on optimization.
DOOM (2016)
Rune and weapon mod picks meaningful.
Kirby's Pinball Land
Learning table layouts and bonus triggers raises scores
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.