yeah sound wise it does have it's NES moments but... hmm the ambient sounds are excellent! and thats coming from a trained (but rather drunk at the moment) audio engineer!
Sfxr is fine for a lot of stuff. Random stuff gets you "retro" sound effects. Or more accurately, the old games used random beeps as an excuse to have sounds
Heh, after I finish my thesis, I'm going to look into creating a better sound effect generator. Might not be free, though, would cost around $10 or $5 if it's not bad
Disclaimer: Any sarcasm in my posts will not be mentioned as that would ruin the purpose. It is assumed that the reader is intelligent enough to tell the difference between what is sarcasm and what is not.