Reuploaded, the previous version of the theme had a error in the animation of the bottom screen, now it is fixed.
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Once again, both the top and bottom screens are a collection of different sprites and resources from the game. I take (almost) everything from TSR (thanks to all the people who ripped the sprites I used for this theme! more detailed credits down below). The color palette of the buttons is based on the colors of the Japanese logo of the game.
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Credits:

Yoshi sprites by: DogToon64, emi3 and Murphmario. Baby Mario sprites by: Dazz and tonberry2k. Grinder/Ukiki sprites by: Murphmario. 3-2 level by: Barack Obama. Forest background by: Barack Obama, MarioFanGamer and Nemica. Intro backgrounds by: MarioFanGamer.
Sound effects by: Raccoon Sam and Yingchun Soul.
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More things:

-This theme has custom sfx (from the game, taken from The Sounds Resource).

-The bottom screen is animated, it's nothing impressive at all but I made it (although, for this version of the theme, I have changed the order of one of the frames of the animation and replaced the star with the flower).

-The game logo now has its original color! (but I still cut out the "SMW2").

-The baby Luigi sprite was edited by me, I just cut out the head ( :o ) of one of his sprites from the end of the game and pasted it in one of the mario sprites, nothing impressive but I just wanted to include Luigi in the theme but without him being in that bag. (also, sorry if it looks a little weird, I'm not a sprite artist, I tried my best).

Aboveground - Koji Kondo