Oh, man...this is just plain fun to listen to! It's so catchy and bouncy, instrument samples are clear as a bell, and the occasional tempo increases really lend themselves well to the overall vibe. Very nicely done.
On a funny side note, I was originally planning on making my contest track out of only short, non sustained instrument samples, but that idea went out the window pretty early on. Worked out beautifully for you, though! ^___^