Firstly, the guitar and synths sound great, but they aren't mixed correctly and drown all the other features of the track. If you, for example, EQed out the low end of the synths, each instrument in the track would be way more defined. Also, the drums are not loud enough (especially the kick!). Finally and most importantly, the 808s are not in tune with the melody. I recommend sitting down and tuning the 808s tediously until you get a sense of what is in key and what isn't.