I'm playing Dungeons of Dredmor on Steam, with Mac OSX Snow Leopard. Every single game I play, I never see any diggles burrow or pop up next to me. I think this might be a bug, but I'm not entirely sure. It might be working as intended, maybe I have an outdated version, or maybe it is a bug. I can't really show you the saves since it's a Core-based thing and not save-based. Maybe one of Essence's Essential Rebalances(the one implemented in Vanilla) might have something to do with it?
This is only in the beta. I'm not sure if I put an OS X beta up. Man, one of these days I need to actually finish this stuff.
Hopefully there will also be some modding improvements, like the ones suggested by Alistaire in: http://community.gaslampgames.com/threads/developers-please-expand-the-modding.6607/ by the way, just between us, my IRL first name is Nick. Arron Syaoran is just my screenname. In IRL I have the same first name as you.
I see HP numbers only when I do damage to the enemy. If there's supposed to be a constant HP text indicator then I'm playing an older version.
Yes, it's supposed to show HP of all enemies (in the tooltip box) at all times. Try updating it by going to your game's preferences, and turning Beta on.