It seems to me they either had an lfo controlling the volume or lfotoo/kickstart controlling the volume. Its ducking every 1 beat so 1/4 measure. The sound itself sounds like an organ and a suttle saw wave panned to the right.
Mostly this I'd, say. All of the little grooves that aren't from that are mostly likely due to the attack of the synth + MIDI input. from there the sidechain ducks that, so it gives off a very rhythmic feel. As for making the actual sound that is also pretty spot in imo, sounds like it's either an additive synth that has many high harmonics shared by organ and a sawtooth waveform, or could a wavetable synth that has separate oscillators making the organ sound and saw. It is also likely that they used some organ sample and layered it with a very simple saw synth. Like i've said before somewhere on this forum, sound design has so many parallels and different ways of getting similar sounds, so if you experiment around with these things you should be able to get pretty close to what you're looking for!
