The NuAlias song you linked has a pretty basic lead synth. Without being able to check with an actual synth, it sounds like three saw waves; one an octave higher and one an octave lower, with a low pass filter on it. Set the filter env to low everything, with about 250ms on the decay. Then add a some overdrive and EQ out around the 370Hz mark. Boom, there's your synth!

I would say that the thing that drives that particular song is not the synth but rather the midi. It's a really funky midi, and that creates the groove.