Gameplay:

* Too many monsters make one explode and kill the adjacent ones plus
   any walls?

Sounds:

* Hero is killed

* Gem taken (explosion, freezing, invisibility)

* Egg crackles

* Additional resurrection granted

* Foot steps

GUI:

* Fix the resurrection string in new game window - it causes the
   window to resize

* Add help

* Add "Revert to factory settings" button to preferences

Graphics:
   
* Feedback for gems

   - Explode: expanding wave?
