This was pretty impressive. The visuals really matched the music quite well. The message was strong and clear. Furthermore, the audio you added worked nicely with the cartoon, and everything was well synched.
Here are my criticisms of the work. First of all, your drawings could be a little more clean, or a little more complex. Generally speaking those are the two routes you want to take. If you want to use simple characters, you should clean them up so although they look simple, they are bright and attractive. If you want to use a dirtier look, you should probably use more detail to compensate. This would make the drawings a bit more impressive.
You also might want to work on hands a bit. I only remember one shot where it really bothered me (the guy is shifting gears I believe), but I was once told that when people watch animation, the thing they're going to pay attention to most is the face and the hands. You might want to put in a little extra work to make your hands a bit more impressive.
Lastly, pay attention to scale. In some shots you use it really well. The morbidly obese lady in the small apartment for example. However, in the last shot which is a long shot in which nothing else is going on, we see the logger, who is bigger than a lemonade stand, as big as a tree and as tall as a piece of heavy machinery. You might want to shrink him down a bit, or make everything else larger.
Otherwise though, this is a really cool animation. Well done!