Wait. C# Windows GUI or XNA? It makes a different. Windows GUI is freakin' stupid to work with for actual games. But yea that's looking really good, a lot of polish.
C# Visual Studio (Windows GUI)... and yeah, I know. But it does work, however inconveniently. I actually almost made this in Torque, then got curious about OGRE, but ended up dropping that because it was too bloated for the simple things I needed, and finally just ended up downloading C# VS Express. (Don't get me wrong, I like OGRE, just not for this project)
AlchemyX: I like the Mario feel to it. But the graphics definitely lack consistency. Those green platforms are completely flat and 2D. The character, on the other hand, is somewhat 3D. The shading of the tree and clouds doesn't match that of the platforms. And those grasses are just ugly. The whole thing would look a lot better with a few adjustments.
I'm a SHITTY artist :-) I can try to make stuff look better, but I can't make animations, sprites, or anything else to save my life, so I figured I'd go with an abstract and aesthetically eclectic style instead. At least I can do that much.