If you're looking for criticism...
Then I'll say that i can hear a few clashing notes in here. You may want to try and fix those clashes, as it just kind of makes the song flow less. Other than that, this song is brilliant in its simplicity, and I can't wait to hear what it sounds like at the end.
Btw, why write that you're looking for constuctive criticism if you don't want reviews? How else would you get constructive criticism? At any rate, good job