8 — Bamboo Island

Mostly manageable bamboo country with recurring Master A. and Otta-smack-u ambushes. Disgusting Swamp introduces Shadow Boxer K and is arguably the hardest stage.

Not too hard for the most part, with a few stages that spike — the wiki names Disgusting Swamp, where Shadow Boxer K debuts, as arguably the hardest, and recommends Salon Cat as a workhorse for the whole map.

The two new enemies are both area-attack pressure: Shadow Boxer K is a very powerful Dark brawler — high health and attack, non-stop hits, quick feet — balanced by short range and lots of knockbacks; Rain D. is a fast, high-health mid-ranger who gets knocked back a ridiculous number of times and usually shows up as a bodyguard for something nastier. The closer is Frontier Spirit.