head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Pure Mechanics
Arcade run-and-gun whose one-credit clears demand total spawn memorization and twitch.

Execution · Pure Mechanics
A movement-shooter demanding near-perfect execution chains to maximise style rank against scripted but relentless enemies.
Metal Slug 3 leans Execution (Pure Mechanics); ULTRAKILL leans Execution (Pure Mechanics).
ULTRAKILL leans a little harder on execution, though the gap is small.
Metal Slug 3
one-hit deaths demand frame-level dodging and aim
ULTRAKILL
Style-ranked combat demands flawless movement, parries, and weapon-swap chains
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Metal Slug 3
every enemy wave is scripted
ULTRAKILL
All enemies are scripted; no adaptive human opponent exists
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Metal Slug 3
branching paths vary runs slightly
ULTRAKILL
Enemy placement is fixed and fully readable after one pass
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Metal Slug 3
memorizing spawns is the path to a one-credit clear
ULTRAKILL
Weapon synergies and ranked-route planning form a deep solvable system
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.