Hey! Well, it seems you are tonguing really a lot. Of course, it’s always a matter taste, but the Irish style of playing the whistle (if not any wind instrument) would involve more slurring (some hardcore traditional whistle players don’t tongue at all). I personally do some tonguing from time to time, but only to put some special emphasis on notes, as the distinctive Irish whistle sound comes from all those cuts and strikes. As you are playing this slow stuff, it should be quite easy to integrate this; I realized one or two cuts in “down by the salley gardens”, so apparently you are already capable of it.
Arrgh, and get rid of that cheesy reverb! 
EDIT: Just remembered a recent thread about tonguing (or not) here: