When he went to get some interior decoration for his lair, Snake Man appears to have taken his name to heart. The entire stage is made up of the bodies of giant snakes, save for the last third of it or so, which just hangs in the air over clouds. It's a fun level to navigate, but dangerous if you don't keep up your guard.
As usual, start by heading to the right. You'll encounter some fairly simple enemies here, the first of which is a bouncing gray fellow that will fall to a single shot from your arm cannon. There's also a miniature snake pillar. Two shots to the head will put it out of commission, but be prepared to dodge any bullets it may spew.
Continuing along the hall, you'll encounter more of the same foes, until you reach a ladder leading up to the next room. Here, there are three of the snake heads in a diagonal row. Take them out carefully, then climb the ladder located at the room's upper left corner. This leads up to a rather enormous snake column.
From the top of the ladder, head left slightly, then turn to face the monster. It sends out bursts of two or three fireballs, which you'll want to jump while returning fire of your own from the arm cannon. The writhing floor will solidify once the head is disposed of, and you can proceed safely to the right, to a ledge overlooking a gap and two miniature snake columns extended upside-down from the ceiling. Wait until they've fired so that it's safe to jump, then leap to the ledge to your lower right.
Once on solid footing again, proceed right. There's another snake column not far to the right, just beyond a ladder that leads up to some energy capsules. Defeat it, then descend the next ladder, and from its base head left then drop to the lower portion of that screen.
Now it's time to head right again, where you'll encounter enemies that look like they're carrying miniature vacuums. They use these as shields, then vault over your head and try to charge you from behind. As they pass overhead, a single shot from the shadow blade can take them out, but you might want to save that for the level's boss. If so, instead just take things slowly. When the robot leaps overhead, be prepared for it to land, so that you can jump it when it charges and then destroy it with a few shots from behind.
There are two or three of the vaulting fellows before a ladder that leads up to the next room, where a robot is swinging its mace. Hit it when it's weakened (or stand below it and throw up some shadow blades, if you prefer), then use the ledge it stands on to reach the ladder to the upper right. Climb that and you can collect random goodness from the canisters before dropping back down, defeating the robot again, and climbing the ladder to its upper left.
This ladder leads to the second of the giant snake columns, and you'll dispatch of him the same way you did the previous one. From there, continue right and take a long leap over a wide pit, which finds you at the base of three gray towers. Climb the furthest one to the right after avoiding the vaulting robots, and at the top of that tower turn left. There's a robot patrolling the ladder there, so take out the robot, leap to the ladder, and climb to the top of the center column.
From here, you now have to work over a series of treacherous jumps that for the most part hang over a bottomless pit. The first jump you'll take is to a solid ledge, and from there you will see ledges with grating. When you stand on these, they send up chariots you can ride. Be careful not to stand on the edge of any of these ledges, but rather toward the center; stand on the edge and you'll be pushed to your death when a chariot emerges.
Using the chariots, you'll want to proceed cautiously to the right. Along the way, cloud-encased bullets glide lazily toward you and will knock you from your perch if given the opportunity. Shoot them to dissipate the clouds, at which point the bullets will move more speedily across the screen. This is a good way to get them out of your way if needed.
Eventually, you'll run out of the ledges that produce chariots. The last few jumps must be made over a series of the narrow green blocks, and you'll have to proceed with caution if you're to avoid being knocked to your doom. One bit of advice is to never be struck while on the far left side of a ledge. Instead, if you see a blow you can't avoid, try and be on the right side so that as you're knocked back, you don't lose your footing entirely.
When you reach the other side of that dangerous gauntlet, you'll be at the gate leading to the area robot master.
NEXT: Gemini Man