Hm.
I wouldn't worry about the mastering yet, what I would do is
a) have more fun while making audio, because out of your review responses it seems like you're pressuring yourself to get better in no time,
b) experiment with countermelodies: if you're using two synths, have them play different lines - in this case, the theme is ascending, so you might want to add a descending melody. Also, a syncopating bass line, that co-operates with the kick, works wonders.
Your beats are fine, I dunno if they're pre-made or anything but I don't really care, as long as it triggers you to be imaginative. Just keep submitting but I'd say make your stuff a little longer so there's more to talk about. Don't worry about your potential.