this sounds mad. the 808 sounds muddy in the mix though. needs more power. also the main melody gets repetitive for some time. add some little variation.
I mostly with agree with the poster above me: the 808 is muddy but you can fix that with some eq-ing. Also the drums and the sounds used for the melody sound low-quality unfortunately.
Try to add some other percs, sound effects, or drops to add some variation and make this beat more interesting. Keep working at it and re-upload it if you make any changes.