The first section introduces two new enemies, Nitron and Bomber Pepe. The former moves across the screen from the right, after which it dives down in a arc while spitting three fire balls that create a wall for a moment, similar to Heat Man. Luckily, it can be destroyed in one hit. The latter jumps forward now and then while throwing explosive eggs, and takes six hits to kill.
This area is littered with both, combined with a pit now and then, making it the hardest starting area for a stage we've seen so far. The difficulty curve works well, with Nitrons appearing in twos and getting closer to the holes as it goes on, until finally we reach two over the last hole with a Pepe on the high ground.
Proto Man appears once more, this time opening the way instead of fighting us. There's an extra life as a reward for pressing against the left wall on the way down, or using Rush. This time, we at least have to think about his placement a bit to get the reward-- assuming we don't have Rush Jet, anyway.
The next few screens are filled with enemies simply called Poles. They appear as eggs and block your path until they're shot, after which they'll hatch and slowly chase you. There's a little puzzle to get a random item here though again, Rush Coil works fine too.
Not much different here. Though it's easier to just use Rush to get up here, it's possible to jump up and around from the small gap.
Here we have to deal with two Penpen Makers while avoiding the Penpens they crank out, along with a few Yambows. They take ten hits, but only take damage in the eyes, while the Penpens can be destroyed or jumped over.
Here we have the only appearance of water in the main stages, with a harrowing set of platforms above it. We need Rush just to start this section, and he remains useful for giving us a boost back up after collecting the items below. The last new enemy here is Gyoraibo, who fires missiles at us as he passes underneath...
...which then explode, and can easily knock us off of given that most of these platforms are single blocks. Things get even messier once Yambow shows up. This is easily the most difficult platforming challenge we've seen in this game, though it rewards the player well with two E-Tanks and an extra life for the taking.
The last two screens are simple in comparison, acting as a breather between this and the boss room.
This stage presents a solid and varied challenge throughout, with a puzzle-like area between two great platforming sections. Rush Coil sees a lot of use here, and requires a little more thought from the player than usual. The Penpen Maker was less interesting than the other mini-bosses we've faced, but the nearby Yambows added some spice to those fights.
The graphics were also impressive, with two different terrain types and a crystal web-like thing in the foreground, the latter two of which are animated. The music is yet another quality piece.