Very nice work.
Well, I enjoyed this very much. Pretty good for played by ear, there were only a few things that you messed up on that i could hear. In the first melody sequence (first loop) at about the end of the three second mark you missed 1 note it was a key lower than it should have been (not that it really matters that much, just thought you would like to know.) Also at the end of the first loop you had (before it moves into the next) you're melody went 'low-lower-low-high' and in the actual song it goes 'low-lower-high-low' but the way you made it actually sounded really cool =D.
now im not trying to be critical, its just one of my favorite songs and i thought u might want to know XD, i have the song file, i can send it to you when i get home. (im at my dads atm)
great work!
- Aaron