Hmm... Not bad.

However, what makes this song sound a little boring is that your melody stays on the same level (a.k.a. it keeps repeating without any major harmonization at the later parts).
If you are looking for the Halloween sound, consider a ghostly sound instead of a mechanic sound, as the mechanic sound makes the song sound like a typical Newgrounds song. If you want your song to stand out, do something that no one, or hardly anyone, has done before.

Thus, you deserve a 4/5. :D