Lafiel on 11 October 2009
the best way to get them is to kill the crystal gecko in 2-1 (not the one at the entrance, but the one that is right before that ambush in 2-1 where there are Miners with flame swords and rock throwing miners)
snipe the Gecko after you finished the ambush from behind - the gecko will run up to the cart (if you can't kill it with one arrow) making it a perfect target for additional hits
