Axolotls: press the UP arrow key to become an axolotl (is rebindable), you'll get an achevement if it worked. by pressing the UP arrow key again, you can sacrifice one level to heal back about 4 hearts, you are naturally faster and of course can breath underwater but take damage and are weakened on land.
gambing: press G to enable gambing! (is also rebindable) with gambing enabled, every time you right click a block, you will either be healed to full and gain absorption, or you'll be slowed and on half a heart.

