possumnater: make more gems, pile them in a certain area (about 5-8 gems), and make a bunch of trenches in there. for the final boss once he passes that trench area (because he will, he is too strong) quickly transfer those gems over to the end of the boss's road so the same gems can fire again. that's how i did it and it worked perfectly.
LOL BIG GLITCH
If you press enter right before u get a battle (very hard to time right) and then exit out of the menu, you are walking around in the map, while in a fight.