Oh yeah. I have a lot to say here

Let's start with Wario Land 2.
The very first world (aka chapter) i set entierly in Wario's (the protagonist's) castle. I really dont know any other games where a world takes place in the hero's home. If anyone knows, let me know

The second chapter mixes manages to mix 4 different themes: garden, forest, seaside with flooded caves, and a ship. It's a very well done chapter. The music in the third level (get in the tea cup) fits the seaside theme perfectly, and those Seagles flying in the sky. I think it's an amazing atmosphere.
And of course, when you are on the ship, you can stop the pirates from sailing away eather by droping the anchor, or flooding the ship.
And like ShyGuyXXL and CM30 already sayd, shen you flood the ship, you get to play the same level again. But it's filled with water. Some of the walls are destroyed by water, some walls stay destoryed after Wario himself destroyed them. But the level layout is very simillar. Even the treasure room is in the same exact location!
And then it goes to Ruins At The Bottom Of The Sea. Flooded ruins, right? No. Just ruins, that have very little water in them. Ok. But what's this?
Ok, I'm getting a little of topic. But just listen: these are ruins at the bottom of the see. You would think they would be flooded. However, there's really little water in them. There is water outside of the ruins thought. On level 3*-4, Escape From The Ruins. Look at this. This water is used for decorations, to show the outside of the ruins. You can't even get there. But Nintendo even put fish there. That's attention to detail.
But getting back on topic. Normal Chapter 3 is Maze Woods. Well, these woods are kind of generic... and Chapter 5 is the Villan's castle. No suprices there.
It's Cahpter 4 that's really interesting. Every level of it is different. Story 1 is set on the train level, one of only 2 in the game. Story 2 is the outside of Nintendo HQ skysqraper, we climb the building. Story 3 is indoors. Story 4 is in a factory. And story 5 in the overall town explorarion, with an awesome boss.
The remaining 2 secret chapters are a haunted mansion (which is overdone in games, and yet they still did something unique. They mentioned to give you a "This Was All A Dream Ending", and turn it into a "Dream Of Things Yet To Come". Creative). And then there is anothe rchapter, with 5 more factory levels. Factory levels are really underused in videogames, so this is a great enviorment.
Oh yeah, and there's chapter set in Wario's castle too, but this time we storm the castle. Explore entierly different rooms. And it becomes harder. A castle that was friendly before seems kind of dangerous. That's 2 chapters set in the hero's home, yet each of them feels different!
EDIT:
Oh, and I competly forgot to mention the place where the Really Final Chapter takes place. Where is this supose to be aniway? A bizzare place, rather than a castle for the final level. Creative? I would say so!
......
Right, time to move on. What do we have in Wario Land 3? We have 2 forest levels, a friendly forest (more like the edge of the forest) where all 4 treasures are required to unlock the final boss, and a dangeorus dark forest, which is a completly optional level. We have a village and a town. Nice. We have water levels that are rivers, lakes, pools, and not oceans. That's different. We have a bridge, a castle and tower with puzzles but no boss fights. And the Warped Void, which is... A completly different enviorment.
......
And in Wario Land 4, nearly every level theme is unique, or underrated in videogames. Another factory, a dump. The ice level is inside a giant fridge? And a pinball machine? A board game and domio land? And Arabian theme level? A cave there hell freezes over?
.......
yeah, there's deffinetly a lot of creativaty there...