Need help with three themed dungeons for a campaign!

[Mad Max]

I'm drafting up an idea for a campaign when the one I'm in now wraps. The basic premise is that this evil explorer dwarf tricks the party into going to a bunch of portals and opening them, which lets him start summoning an army. After a while dealing with this guy's evil plans, the group would have to revisit each portal dungeon and close the portal, but each dungeon has been twisted to a more evil version.

So the thing I need help with is coming up with three dungeons, each with their own unique feel, and then a way to twist them on their heads and make them fun to do a second time. Like, swamp dungeon that, when revisited, is flooded completely.

If it helps at all, I'm drawing inspiration from the 4e monster "Foulspawn" for the campaign premise. They are basically people who wandered into another plane, went mad and were magically mutated. I also intend to institute a madness rule/run it as action-horror. Any help would be appreciated!

[Saintheart]

Dungeon on Positive Energy Plane ... which when they revisit it, has been entirely hurled onto the Shadow Plane.

[Lvl45DM!]

Land, sky and sea!

A simple jaunt through a humanoid infested cave complex that becomes spelunking through a horrific chasm, filled with magma and toxic mists, climbing along sheer walls and struggling to fly through thermal updrafts and lava sprays.

Exploring an exotic deserted island full of dangerous wildlife and the ruins there, but the Island then sinks into the ocean floor, haunted by the rotten bloated corpses of all the wildlife as well as darker things coming up from the abyss to feed on them.

A sky castle floats majestically, if erratically, its original owner long dead, inhabited by many flying beasts making it their home, comes to life afterwards the very castle itself seeking to destroy invaders with animated armour and golems and self firing ballsitae, the cloud it floats on becoming a thunderhead

Adding in a good guy in every location, a dwarven prisoner who used to own the mine, a hermit druid who tends to his garden in the ruins and a powerful wizard trying to figure out the castle, lets you turn them evil too

[Crake]

Dungeon on Positive Energy Plane ... which when they revisit it, has been entirely hurled onto the Shadow Plane.

Why the shadow plane and not the negative energy plane?