This is an ABFH remix contest judge's review.
The mic seems clear enough. The instrumental seems quite soft compared to the voice; a good thing would be to have it as balanced as possible, with the voice taking a bit of the forefront. But more on the instrumental later, let me move on now with commentary on the voice.
Your general pitching is alright, apart from some higher notes that you're struggling with ("And now I know that I'm really home"). It's almost like you're hitting the ballpark pitch, but not the exact one.
Also, timings. Sometimes it seems as though you're coming in later than normal. How straight or swing-like the rhythm of your syllables is will change the feel of your cover accordingly. Basically, the instrumental sounds like a swing, laid-back and easygoing — roll with it, don't fight it. Feel the sway of the music as you sing.
Your voice has a breathy quality that, with more practice, would capture the spirit of this song and much more. Please keep practising — try to imitate down to detail what you hear, in order to get an idea of how a person sings and feels a song, in order to learn. Do that for as many songs as you enjoy. Then, you will be able to even put your own spin.
One final thing:
On Newgrounds and nearly everywhere else, a cover implies a complete remaking and arrangement of the instrumental (unless it's an instrument specific cover; in this case, it's a vocal cover). Because it said this is a cover, I was hoping that you were going to make an attempt at an instrumental for this. I understand what this is now, though I hold the hope that this might help kindle an interest in remaking instrumental versions of songs, or even producing. :)
All the best in the competition!