Probably just the midi, but measure 17 sounds like crap where you have let ring. I would definitely move for a softer tone, clean with delay or acoustic if you're going to actually record this.

Also, to be honest, I thought the low tuning was extremely unnecessary. The main riff sounds dragged down, especially being in a major key. It really just doesn't add anything to the song.

The song itself I didn't find it bad at all, I think at parts it dragged on so maybe add parts to liven it up or do a little editing to keep it interesting. But it was enjoyable, so good job.

If you want here is one of my pieces: https://www.ultimate-guitar.com/forum/showthread.php?t=1355888