Why should I buy the full version when I've got the Light version? What does it have that makes it worth the extra money?
The light version just includes the basic, common dice (d4, d6, d8, d10, d12, d20, d%). The full version has so much more, including exotic dice such as d16, d18, d24 and d30, as well as support for d1000 and d10000, support for all kinds of open (aka "exploding") rolls, and most importantly, formulas, character sheets, widgets, and much more. And with those formulas comes additional features such favorite rolls, access to a database of formulas specific for a wide range of games, and additional customization (including both custom dice with whatever you want on the sides, as well as custom roll macros that determines their behavior when rolled).
How do I get rid of dice?
Tapping the trash can will remove all dice. You also can tap on one of them and select "Delete" from the alert.
Why do the dice seem to keep moving and jumping around?
If a die lands crooked (due to being wedged against the side or another die), it won't count until it lies flat (or at least close enough to flat). As a result, cocked dice are "jumped" a bit to get them to try to land flat (and yes, sometimes this will result in nudging other dice to make it happen). In worse cases, one die lands on top of another die, which is not allowed either, so it also will jump around until it pushes the lower die out of the way or finds a spot to land correctly.
Sometimes there aren't dice on the bottom bar, and then they appear, one after the other - why?
The die bar at the bottom contains a rendered version of the current dice, so if you change their textures (for example), the dice need to be re-rendered, so as to correctly reflect what is actually rolled.
How do I tilt/rotate the image so it's not an overhead view?
Twisting with two fingers will do the trick.
Can't I customize what dice are shown in the bottom bar?
Nope, that's a feature only found on the full version of The Dicenomicon