Dragon Egg!(1991)

Dragon Egg! is a 2D platformer where you jump and attack enemies as you make your way through linear stages. You start off only being able to hit enemies up close with the dragon egg, but you can find fire orbs dropped by dead enemies. When you collect enough of them, the egg hatches and the dragon will breathe fire from a distance. Grabbing more orbs causes the dragon to grow up, gradually increasing the range of your attacks and even giving you a slight hover at the highest level. The game also has a currency system and stores, which can provide additional fire orb power-ups and other useful tools.