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
Flawless execution of memorised patterns under one-hit-death pressure.

Execution · Practiced Mastery
A neo-noir one-hit-kill action platformer about planning and replaying perfect assassinations.
Contra 4 leans Execution (Pure Mechanics); Katana ZERO leans Execution (Practiced Mastery).
Contra 4 leans a little harder on execution, though the gap is small.
Contra 4
One-hit deaths under dense bullet patterns demand near-perfect inputs
Katana ZERO
One-hit-death slashing and deflects demand precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Contra 4
Every enemy and boss is a fixed script
Katana ZERO
Enemies follow fixed placements and behaviours
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Contra 4
Spawns and patterns are identical every run
Katana ZERO
Rooms are identical on every attempt
Katana ZERO leans a little harder on optimization, though the gap is small.
Contra 4
Memorising layouts and weapon routing enables the execution
Katana ZERO
Planning the perfect room-clear sequence
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.