I just got as far as I could with the web version, and yes, I really enjoyed the challenges.  I understand if there are more bosses planned, that's great... but in the meanwhile, are you intending to put in an endgame, and if so, when?  I'll note that one of my favorite roguelikes of all time, Nethack (okay, yeah, I'm old!) had an endgame even though they kept improving it and adding more features (side dungeons, archdemon lairs, and more).