Wow, this is...this is a pretty good level! And to think that, not long ago, you made stuff like Plok Boss and Trapolague. You have certainly improved, and for that, I congratulate you.
Anyway, my review:
So, the level begins simple enough, but not long after the start, a Toad informs the player that "there no water" in the swamp, and the goal of the level is to bring the Toad water. Also, the Toad is standing on a pipe that's in between two others, and none of these pipes have blocks below them, which is a weird decision since the player can easily jump back onto one of the pipes if he/she falls down. In the second section, the player comes across a bright green vine despite the fact that the palette of everything else has been muted. Also, some of the tree trunks are foreground images which causes cutoff if the player jumps between them and the background images:
I recommend making either all of the tree trunks background images, or make duplicates of the foliage's sprites as foreground images.

After that little section, the player ends up in a small castle, where when he/she hits a skull-switch, waterfall backgrounds come falling down from a hole in the ceiling, though I think it would be better if it stopped partway (so that the waterfall graphic stretches from the top of the section to the bottom) instead of having the top graphic fall with it. Then a door just sorta appears, half-connected to a sizable. After entering the door, the player is informed that the Toad already got the water, brought it home (or maybe he's saying that he will take it home; I can't really tell), and bypassed the player to inform him/her of all of this. After that, the player gets a star.
Summary:
GOOD:
-Graphic choices aren't terrible.
-Music choice fits the level well.
-Block placement is well done.
-NPC placement is good, but a bit sparse.
BAD:
-Having background images in place of blocks for the pipes is weird.
-The bright-green vine in Section 2 is out of place and should be recolored to fit with the rest of the level.
-Background/foreground issues (see screenshot).
-The story is a bit rushed and has a few plot-holes and grammar mistakes.
-The door that appears at the top of Section 3 looks awkward by being half on the sizable and half not. Pick one or the other.
-The level is short.
In conclusion: Aside from the level's short length, all of the level's problems are minor and don't detract from the experience much. I'd say this deserves a 6/10.