The real ending to Hell Temple was Lameza becoming possessed by The Mother.The Treasure and the Fan Disservice picture were just Lameza's crumbling mind coming up with a symbolic representation.
If Lemeza dies during the final boss, all of humanity dies.Allow me to quote the intro of the Wiiware remake. "...This is the day Humanity was born. Then when they angered her, they were destroyed.". Fighting her is pretty sure to annoy her, and, well, note the fetus ball in the background at the end - This could be the first of a new breed of human, destined to take the place of the humans when they were obliterated. Thank god for Lemeza putting her to rest before she could do that. But if he died and the Mother remained alive...
The fetus and the energy being are BOTH the MotherA big argument among fans is debating whether the energy being you fight at the end is Mother or simply the guardian of Mother since the fetus in the background cries out the Treasure of La-Mulana. My theory is they are both Mother. According to the in-game text, Mother is immortal. If you defeat her physical form (the head you fight initially), she will simply be reborn. That's why you have to find the Elixir which gives form to Mother's soul. I think that's why a fetus appears in the background during the battle: Mother is trying to revive herself but can't fully do it since her soul is currently ripped from her body. Once her soul is killed, Mother's body finally dies (the fetus disappears and the ruins, Mother's body, crumbles).
Lameza's daughter in La Mulana 2 is created from the Secret of Life that Shorn stole.