The Gary Jules cover of Mad World (which would make your song a cover of a cover I suppose) is not instrumentally complex, and focuses mostly on the power of Gary Jules' singing. Minor gripes aside, you did a pretty good job replicating that feeling. Your minor instrumental expansion of the Jules cover is good as well. However, my main issue is about your singing. Because of the spartan nature of the instrumental accompaniment, your voice is under a lot of scrutiny here. It was easy to hear when you were off-key. My last criticism (which is pretty subjective) is that your voice seems to be a theater voice. This wouldn't normally be a problem except for the way Mad World was sung by Jules and Tears for Fears. Their tones were distinct; Tears for Fears had an paranoid, manic-depressive feel, while Jules was more melancholy and constant in his tone. While I get that this is more of a cover of the latter than the former, your tone just doesn't feel right to my ears. It sounds more like you're trying to convey a story with your voice, rather than pure emotion.
Like I said, take the last comment with a grain of salt, because that's just my opinion. I think the effort is there but, at the risk of sounding like a pretentious music-douche, your voice just doesn't match the musical mood like it should.