Knither

Knither is the sequel to Demon Crystal. The gameplay is similar - collect keys to open locked areas, find the big key and then the exit, only now you also have to collect 3 passwords per world, otherwise you cannot advance to the next world. In addition to the fire ball, there's also thunder sword, wave of fire, cracker and spark flash, which kills all enemies on screen. The game features 5 worlds with 10 stages each, plus the last stage where you battle the witch, for a total of 51 stages.