Fist of all let me say that I enjoyed listening those songs. I think they are very nice.

About the soundquality/mix I would want to say that the mix (volume-balance) is not bad at all, but some things were a pity:

First of all: what's with the wobbly sound (guitar?)
The ending chords are cut off in a pretty bad way.
Ducking (the compression or volume automation where the music is getting softer in volume when the vocals come in) should be not so drastic and audible . This was the case in the first two songs.
Here and there there is some distortion/crackle

I'll be back...