A number of different variables in the game do not have any protection from wrap-rounds, meaning that making the value too low will cause it to flip over to a very high amount, or increasing the value too much can result in a very low value. This has the potential to affect game balance heavily, possibly even fatally.

Known examples:

-Piety wrap-round. Continuously praying will reduce piety more and more, until it wraps round to an extremely high value, allowing for easy precrownings. (Though some method of dealing with the deity summons is needed to abuse this it is still very exploitable.)
-Gold wrap-round. Increasing a stack of gold beyond 2 billion will make it become negative gold, which behaves buggily and can crash the game. (this level of gold can be reached with dragon gold-doubling, potentially another bug in itself)
-Moloch armour bug. A monster with low dexterity that equips moloch armour will have it's dexterity wrap round to a high amount resulting in it being insanely fast. This becomes a game-ending issue when a threat room of greater molochs is encountered - a super-fast greater moloch will kill most characters rather quickly.

These are the only 3 known to affect gameplay, but other such bugs may exist undiscovered or unexploitable. I've grouped them in the one report as they have a common cause and solution.