Yeah, there's a fairly brittle quality to this. The guitar sound is too bright and clicky for my taste. The vocal is very sibilant. The NT-1 is probably largely to blame, as it is a rather bright mic. It can work great for some things, but can get harsh. You might try a good de-esser on the vocal track. Some EQ might help the guitar, but it would be best to retrack and try to get a smoother sound.
Decent song, though.