upgrading the dice is easy :) Just drag a die onto the table in front of the wizard like the text says :D It will pick and upgrade a random side type (so all attacks on the die will increase by +1, for example). But there's an increasing failure rate chance the more you upgrade your dice, which will turn *one* side of the die into a useless Skull!
changing the health/armor on the bug is a great idea for sure! Thanks for playing the game!