At the end of the day, the track is what you said it is "a demo". A very rough, one take, live demo by the sounds of it
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Im assuming it was recorded in your practice space with little more than x1 maybe x2 mics.
Thats totally cool, so keep that in mind when reading any feedback, as the song itself has plenty of room for developing
Theres is def an arty vibe, to the song itself ( reverb and effects aside ) the guitar effect is cool and the drown vocals suit the arty thing.
Posting on here at this stage wasn't gonna get you much feed back, cos too much of the song is missing, I assume.
The drums and the bass line will play an integral part in keeping what you have both together and keep the listener listening, look forward to hearing more.
I appreciate a demo has many stages but this stage may not be ready for constructive feedback yet except, It sounds like it could be really good.