I was actually going to rate this lower until I saw the ending, that was pure brilliance. These Rube Goldberg flashes always tend to amuse me, kudos for thinking up these intricate plans and then animating them. The animation was done well, and I thought the song went along great with the animation. The sound effects were somwehat childish though and didn't really mesh too well.
I liked how at the beginning you split the screen to show the two sides of the machine that were working at the same time, it kept me even more focused on the flash. Overall, it was an impressive and well done flash with a hilarious punchline. I hope to see more funny flashes like this from you in the future. Keep up the excellent work!