4 — Swimming Cats

An easy sea crossing with one ironic spike: the FIRST stage, Premature Launch, and its two Master A.s is the hardest thing here.

Easy throughout, with the difficulty curve installed upside down — Premature Launch, the opening stage, runs two Master A.s and is harder than anything that follows, including the closer Salty is Seawater.

Two new enemies debut: Duche, a slow-ish all-rounder with a quick double-hit attack, and THE SLOTH, a high-health, high-attack wall with a slow attack rate — the wiki's comparison is Bahamut Cat — who exists to stall your push for as long as you let him. Both become recurring Legend Stages furniture from here on.