Oh, this might be cool at the end.

Imho:
- Balance between bass and the rest is wrong. I'd dial the bass back like 3db and sidechain it (more) by kick.
- That chord synth (0:14) is cool, but it needs something. Like some smooth filtered distortion, or some modulation.
- 1:30 ... nice. I'd add a detuned/modulated layer to the lead or some delicate string-ish synth underneath the lead playing chords of the track.
- Melody variation as you said.

Very cool track. I agree with the bass comment, just a bit loud. Really like the change of pace at 1:30 and the unnatural percussion (if that makes sense). I enjoy minimal style songs like this. If thats what your going for then cool.  Don't feel like you need to add too much, sometimes less is more, but make the sounds you got sound full/strong!

make kick punchier, add more movement to the track (tremolo n stuff), make it less repetitive