I don't have my own monitoring equipment available right now so I cannot say much about the bass sounds but the demos would be better without the lead sound, just a drum loop and changing the bass sound and maybe the notes too. I would have mixed the bass louder if you want to demonstrate exactly the bass. I also found many of the bass sounds very similar. It's also difficult to listen to the bassline because I don't listen to that kind of music (of course not your fault). I usually listen to etn.fm trance & progressive channels.
Btw, Darude is a finnish dj / producer.
